[LAD] Attenuation of sounds in 3D space
Continuation of talk from Re: [LAD] Floating point processing and high dynamic range audio Simply Subject line no longer described the actual content. On 2010.07.21. 20:19, Jörn Nettingsmeier wrote: On 07/21/2010 08:56 PM, JohnLM wrote: If I code program to handle attenuation of sounds depending on their source (emitter) position in virtual 3D space, I guess then there's no simple way to relate the effect to real world. How this is usually handled? you reduce the level with distance (amount depends on whether you are in the near or far field and whether you have a point, line or planar source), and attenuate the high frequencies to simulate air damping. if you're in an enclosed space, you'd also want to take into account the dry-to-reverb ratio, and ideally simulate correct early reflections. Thanks! Though this is quite sophisticated. I currently only worry about sound (pressure) level. I will try to implement the rest when the current code actually works. Well I have a set of (omidirectional) point sources. The code currently has no information whenever given space is open or enclosed. (I guess open or empty space is implied then) As much as I can understand the sound pressure is inversely linearly correlated to distance. p~(1/d) or p=k*(1/d) where k is currently undefined constant coefficient. What's the thing about far and near fields? On Wed, Jul 21, 2010 at 2:01 PM, wrote: An audio signal represents pressure variation as a function of time. Multiplying it by two will give 2 times the pressure, and 4 times the power. The subjective result is another matter. Ummm... is it sound pressure or sound pressure level? Or it doesn't matter? (are they equivalent?) On 2010.07.21. 20:40, Ralf Mardorf wrote: I guess the transit time issue for analog isn't solved. When I worked for Brauner we and SPL developed a surround microphone + SPL mixing console. IMO it's pure bullshit. http://audio.uni-lueneburg.de/seminarwebseiten/audiomedien/frst/material/ICA5.jpg http://audio.uni-lueneburg.de/seminarwebseiten/audiomedien/frst/material/asm5.jpg Perhaps today there is math for virtual effects, I don't know, but I would be very sceptic. I'm sure any digital alogrithm are far from perfect to represent the acoustic attenuation (and related) effects like in real world. But it just need to be close enough. Ummm... I somehow fail to see how the microphone rig is related to this. ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On Wed, 2010-07-21 at 22:07 +0200, JohnLM wrote: > Continuation of talk from > Re: [LAD] Floating point processing and high dynamic range audio > > Simply Subject line no longer described the actual content. > > On 2010.07.21. 20:19, Jörn Nettingsmeier wrote: > > On 07/21/2010 08:56 PM, JohnLM wrote: > > > >> If I code program to handle attenuation of sounds depending on their > >> source (emitter) position in virtual 3D space, I guess then there's no > >> simple way to relate the effect to real world. > >> How this is usually handled? > > > > you reduce the level with distance (amount depends on whether you are in > > the near or far field and whether you have a point, line or planar source), > > and attenuate the high frequencies to simulate air damping. if you're in an > > enclosed space, you'd also want to take into account the dry-to-reverb > > ratio, and ideally simulate correct early reflections. > > Thanks! Though this is quite sophisticated. I currently only worry about > sound (pressure) level. I will try to implement the rest when the > current code actually works. > > Well I have a set of (omidirectional) point sources. > The code currently has no information whenever given space is open or > enclosed. (I guess open or empty space is implied then) > > As much as I can understand the sound pressure is inversely linearly > correlated to distance. p~(1/d) or p=k*(1/d) where k is currently > undefined constant coefficient. > > What's the thing about far and near fields? > > On Wed, Jul 21, 2010 at 2:01 PM, wrote: > > An audio signal represents pressure variation as a function of > > time. Multiplying it by two will give 2 times the pressure, > > and 4 times the power. The subjective result is another matter. > > > Ummm... is it sound pressure or sound pressure level? Or it doesn't > matter? (are they equivalent?) > > On 2010.07.21. 20:40, Ralf Mardorf wrote: > > I guess the transit time issue for analog isn't solved. When I worked > > for Brauner we and SPL developed a surround microphone + SPL mixing > > console. IMO it's pure bullshit. > > > > http://audio.uni-lueneburg.de/seminarwebseiten/audiomedien/frst/material/ICA5.jpg > > http://audio.uni-lueneburg.de/seminarwebseiten/audiomedien/frst/material/asm5.jpg > > > > Perhaps today there is math for virtual effects, I don't know, but I > > would be very sceptic. > > > > I'm sure any digital alogrithm are far from perfect to represent the > acoustic attenuation (and related) effects like in real world. But it > just need to be close enough. > > Ummm... I somehow fail to see how the microphone rig is related to this. This is around 10 years ago, it might be that a lot of issues are solved today. Anyway, regarding to psycho-acoustic the artificial head, just stereo, isn't that bad. Just keep in mind that we have two ears and any math or analog recording with more virtual ears is suspect, regarding to a natural impression. JUST 2 cents, Ralf ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On 2010.07.21. 21:20, Ralf Mardorf wrote:
On 2010.07.21. 20:40, Ralf Mardorf wrote:
I guess the transit time issue for analog isn't solved. When I worked
for Brauner we and SPL developed a surround microphone + SPL mixing
console. IMO it's pure bullshit.
http://audio.uni-lueneburg.de/seminarwebseiten/audiomedien/frst/material/ICA5.jpg
http://audio.uni-lueneburg.de/seminarwebseiten/audiomedien/frst/material/asm5.jpg
Perhaps today there is math for virtual effects, I don't know, but I
would be very sceptic.
I'm sure any digital alogrithm are far from perfect to represent the
acoustic attenuation (and related) effects like in real world. But it
just need to be close enough.
Ummm... I somehow fail to see how the microphone rig is related to this.
This is around 10 years ago, it might be that a lot of issues are solved
today. Anyway, regarding to psycho-acoustic the artificial head, just
stereo, isn't that bad.
Just keep in mind that we have two ears and any math or analog recording
with more virtual ears is suspect, regarding to a natural impression.
JUST 2 cents,
Ralf
True. But this is of no concern for my program. It doesn't try to
emulate psycho-acoustics of human perception. IMO that would be a
problem of acoustic engineers.
My program just tries to translate sounds in virtal space to audio track
of one, two, six or whatever else number of channels as best as it can
doing it automatically.
The project was started when the amount of sounds in a video ("foley"
sounds, background effects and such) was becoming more than I wanted to
deal with manually with a DAW. And I couldn't find any FOSS alternative.
If it is of interest to anyone, program (non-working draft of program)
is located here.
https://launchpad.net/mage
___
Linux-audio-dev mailing list
Linux-audio-dev@lists.linuxaudio.org
http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On Wednesday 21 July 2010 21:20:45 Ralf Mardorf wrote: > Just keep in mind that we have two ears and any math or analog recording > with more virtual ears is suspect, regarding to a natural impression. Excuse me, that is bullsh**. Yes, we only have two ears. But that two ears hear sound from all around them they can distinguish between front/rear and top-down for sources with equal distance to both ears trough the unique shape of the head. And surround/ambisonics/wfs is not about feeding a stereo signal to the ears to re-create the signal the ears hear, its about recreating the sources all around the head to recreate what the ears hear (if they were there). And for that you _need_ math and more electronic ears! The more you have, the better[*]! Have fun, Arnold [*] Can be proven by double-blind-tests, just ask your local ambisonics-freak. signature.asc Description: This is a digitally signed message part. ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
@ nonsense and bullshit, where are the examples that it works? There is no valid recording with more than 1 or 2 channels, regarding to a natural impression. Some art projects that didn't try to give a natural impression are something very, very different. Most audio engineers still fail regarding to stereo and mono issues. I wonder about the geniuses who are able to do 5.1 and all the other stuff. Please post links to the geniuses work, but call me names. ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On Wed, Jul 21, 2010 at 4:58 PM, Ralf Mardorf wrote: > @ nonsense and bullshit, where are the examples that it works? > > There is no valid recording with more than 1 or 2 channels, regarding to > a natural impression. Some art projects that didn't try to give a > natural impression are something very, very different. > > Most audio engineers still fail regarding to stereo and mono issues. I > wonder about the geniuses who are able to do 5.1 and all the other > stuff. > > Please post links to the geniuses work, but call me names. ralf, you simply don't have any idea what you're talking about, unless you try to limit your comments to commercially released material. you made no indication that you intended to use this limitation. people have been recording with/for ambisonics for nearly 40 years now. recording with multiple microphones (including things like the eigenmike http://www.mhacoustics.com/mh_acoustics/Eigenmike_microphone_array.html which by itself makes your point null and void) is common enough that sound on sound has articles on it. ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On Wed, 2010-07-21 at 22:58 +0200, Ralf Mardorf wrote: > @ nonsense and bullshit, where are the examples that it works? > > There is no valid recording with more than 1 or 2 channels, regarding to > a natural impression. Some art projects that didn't try to give a > natural impression are something very, very different. > > Most audio engineers still fail regarding to stereo and mono issues. I > wonder about the geniuses who are able to do 5.1 and all the other > stuff. > > Please post links to the geniuses work, but call me names. It's unimportant what are my thoughts about those links, I'm unable to listen, because I'm reduced to stereo, for good reasons. But I would like read what people who do have 3D equipment do feel, while listening to those perfect 3D recordings. I do agree, that 3D could be good, but it never ever will sound natural. There is no perfect building to the context for stereo or mono and there also is no perfect way to use 5 or 7 audio channels. A lot of people, even a lot of those who you respect, tried it and I never meed someone who preferred mono or stereo to surround. Btw. sometimes I do fail too, so I don't insist that I'm not mistaken, to the contrary, it would be a win for me too, if I should fail with my opinion. ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On Wed, Jul 21, 2010 at 10:58:13PM +0200, Ralf Mardorf wrote: > @ nonsense and bullshit, where are the examples that it works? > > There is no valid recording with more than 1 or 2 channels, > regarding to a natural impression. Yo mean you don't know of one. > Some art projects that didn't try to give a natural impression > are something very, very different. You are obviously out of touch with a lot of thing that have happened of the last 30 years. And it's not just 'art projects'. > Most audio engineers still fail regarding to stereo and mono issues. I > wonder about the geniuses who are able to do 5.1 and all the other > stuff. And you fail regarding almost everything you write. If you want to pontificate about acoustics and psycho-acoustics then please study the subject before doing so. It will take some time and efforr but may help you to avoid making a fool of yourself. Ciao, -- FA There are three of them, and Alleline. ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On Wed, 21 Jul 2010 17:10:35 -0400 Paul Davis wrote: > On Wed, Jul 21, 2010 at 4:58 PM, Ralf Mardorf > wrote: > > @ nonsense and bullshit, where are the examples that it works? > > > > There is no valid recording with more than 1 or 2 channels, regarding to > > a natural impression. Some art projects that didn't try to give a > > natural impression are something very, very different. > > > > Most audio engineers still fail regarding to stereo and mono issues. I > > wonder about the geniuses who are able to do 5.1 and all the other > > stuff. > > > > Please post links to the geniuses work, but call me names. > > ralf, you simply don't have any idea what you're talking about, unless > you try to limit your comments to commercially released material. you > made no indication that you intended to use this limitation. > > people have been recording with/for ambisonics for nearly 40 years > now. recording with multiple microphones (including things like the > eigenmike > http://www.mhacoustics.com/mh_acoustics/Eigenmike_microphone_array.html > which by itself makes your point null and void) is common enough that > sound on sound has articles on it. I remember when 2001 first came out, being totally astonished by the sequence where the ape-man first uses a bone as a club. There was the totally realistic effect of a gust of wind moving from the screen to the rear of the cinema. I've no idea what system was in use, but it certainly wasn't 2 channel stereo! -- Will J Godfrey http://www.musically.me.uk Say you have a poem and I have a tune. Exchange them and we can both have a poem, a tune, and a song. ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On Wed, 2010-07-21 at 17:10 -0400, Paul Davis wrote: > On Wed, Jul 21, 2010 at 4:58 PM, Ralf Mardorf > wrote: > > @ nonsense and bullshit, where are the examples that it works? > > > > There is no valid recording with more than 1 or 2 channels, regarding to > > a natural impression. Some art projects that didn't try to give a > > natural impression are something very, very different. > > > > Most audio engineers still fail regarding to stereo and mono issues. I > > wonder about the geniuses who are able to do 5.1 and all the other > > stuff. > > > > Please post links to the geniuses work, but call me names. > > ralf, you simply don't have any idea what you're talking about, unless > you try to limit your comments to commercially released material. you > made no indication that you intended to use this limitation. > > people have been recording with/for ambisonics for nearly 40 years > now. recording with multiple microphones (including things like the > eigenmike > http://www.mhacoustics.com/mh_acoustics/Eigenmike_microphone_array.html > which by itself makes your point null and void) is common enough that > sound on sound has articles on it. Indeed I never heard a recording done with this equipment. Where can I get an example done with this equipment? I can't listen to it at home, but I guess I'm able to find somebody with the valid equipment to listen to the recording. At least somebody from the list, e.g. you Paul does know some studio were I could listen to a recording here in NRW, Germany. Seems to be very common equipment, so that it makes sense to work with it. ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On Wed, 2010-07-21 at 23:21 +0200, f...@kokkinizita.net wrote: > On Wed, Jul 21, 2010 at 10:58:13PM +0200, Ralf Mardorf wrote: > > > @ nonsense and bullshit, where are the examples that it works? > > > > There is no valid recording with more than 1 or 2 channels, > > regarding to a natural impression. > > Yo mean you don't know of one. Yes, I could be mistaken, but I guess it#s nearly impossible. > > > Some art projects that didn't try to give a natural impression > > are something very, very different. > > You are obviously out of touch with a lot of thing that have > happened of the last 30 years. And it's not just 'art projects'. Correct reduce it to the last 10 years, but 30 years. > > > Most audio engineers still fail regarding to stereo and mono issues. I > > wonder about the geniuses who are able to do 5.1 and all the other > > stuff. > > And you fail regarding almost everything you write. If you want > to pontificate about acoustics and psycho-acoustics then please > study the subject before doing so. It will take some time and > efforr but may help you to avoid making a fool of yourself. I guess you make a fool of your self, perhaps not to Linux lists, but indeed to professionals who have to do hard jobs all the day. At least we still have all that phased stereo recordings, that we aren't allowed to send on radio in Germany. > > Ciao, > ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On Wed, 2010-07-21 at 22:23 +0100, Folderol wrote: > On Wed, 21 Jul 2010 17:10:35 -0400 > Paul Davis wrote: > > > On Wed, Jul 21, 2010 at 4:58 PM, Ralf Mardorf > > wrote: > > > @ nonsense and bullshit, where are the examples that it works? > > > > > > There is no valid recording with more than 1 or 2 channels, regarding to > > > a natural impression. Some art projects that didn't try to give a > > > natural impression are something very, very different. > > > > > > Most audio engineers still fail regarding to stereo and mono issues. I > > > wonder about the geniuses who are able to do 5.1 and all the other > > > stuff. > > > > > > Please post links to the geniuses work, but call me names. > > > > ralf, you simply don't have any idea what you're talking about, unless > > you try to limit your comments to commercially released material. you > > made no indication that you intended to use this limitation. > > > > people have been recording with/for ambisonics for nearly 40 years > > now. recording with multiple microphones (including things like the > > eigenmike > > http://www.mhacoustics.com/mh_acoustics/Eigenmike_microphone_array.html > > which by itself makes your point null and void) is common enough that > > sound on sound has articles on it. > > I remember when 2001 first came out, being totally astonished by the > sequence where the ape-man first uses a bone as a club. There was the > totally realistic effect of a gust of wind moving from the screen to the > rear of the cinema. I've no idea what system was in use, but it > certainly wasn't 2 channel stereo! > Was it natural or 'hyper'-natural? ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On Wed, Jul 21, 2010 at 11:24:12PM +0200, Ralf Mardorf wrote: > Indeed I never heard a recording done with this equipment. Where can I > get an example done with this equipment? I can't listen to it at home, > but I guess I'm able to find somebody with the valid equipment to listen > to the recording. At least somebody from the list, e.g. you Paul does > know some studio were I could listen to a recording here in NRW, > Germany. Seems to be very common equipment, so that it makes sense to > work with it. One of the expert users of Ambisonics, a member of this list, is based in Essen. If he's interested he might get in contact with you. Ciao, -- There are three of them, and Alleline. ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On Wed, Jul 21, 2010 at 11:27:59PM +0200, Ralf Mardorf wrote: > I guess you make a fool of your self, perhaps not to Linux lists, but > indeed to professionals who have to do hard jobs all the day. Could be, I'm one of them. > At least > we still have all that phased stereo recordings, that we aren't allowed > to send on radio in Germany. What has that got to do with me ? Ciao, -- FA There are three of them, and Alleline. ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On Wed, Jul 21, 2010 at 5:36 PM, wrote: > On Wed, Jul 21, 2010 at 11:24:12PM +0200, Ralf Mardorf wrote: > >> Indeed I never heard a recording done with this equipment. Where can I >> get an example done with this equipment? I can't listen to it at home, >> but I guess I'm able to find somebody with the valid equipment to listen >> to the recording. At least somebody from the list, e.g. you Paul does >> know some studio were I could listen to a recording here in NRW, >> Germany. Seems to be very common equipment, so that it makes sense to >> work with it. > > One of the expert users of Ambisonics, a member of this list, > is based in Essen. If he's interested he might get in contact > with you. and had you been in Berlin in either july or fall of 2008, you could have listened to a multi-mic ambisonic recording of a performance of Messaien's Meditations on the Holy Trinity, played in the Koln Dom (the first performance was streamed live; the second was a playback of the recording). if that won't work for you, then perhaps you might want to visit any of the theaters outfitted by these guys: http://www.iosono-sound.com/references/installations/ and if that still isn't enough, Nimbus Records have released several B-format recordings. --p ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On Wednesday 21 July 2010 23:18:15 Ralf Mardorf wrote: > On Wed, 2010-07-21 at 22:58 +0200, Ralf Mardorf wrote: > > @ nonsense and bullshit, where are the examples that it works? Here: http://www.ambisonia.com/ Downloaded a lot of cool stuff from there (and will do so once my set-up is finally complete). And even with my "untrained" ears (not as good as Fons' or Jörns or Pauls and not as experienced as yours) they sound great. > > There is no valid recording with more than 1 or 2 channels, regarding to > > a natural impression. Some art projects that didn't try to give a > > natural impression are something very, very different. > But I would like read what people who do have 3D equipment do feel, > while listening to those perfect 3D recordings. > I do agree, that 3D could be good, but it never ever will sound natural. I only have a four-channel square setup (half) working but the recordings from above (note: real recordings from plane-fields, Indian markets and British train stations) sounded _very_ realistic. And as I said, the more speakers, the better. > It's unimportant what are my thoughts about those links, I'm unable to > listen, because I'm reduced to stereo, for good reasons. Even with hearing aids you are _not_ limited to stereo. At least when stereo is "two ears for listening". When stereo means "two speakers for playback", that is rather limiting. But something that can be solved... > There is no perfect building to the context for stereo or mono and there > also is no perfect way to use 5 or 7 audio channels. We are not talking about 5.1 or 7.1 here. These suck big time. We are talking about ambisonics vs. binaurals vs. simple stereo here! > A lot of people, even a lot of those who you respect, tried it and I > never meed someone who preferred mono or stereo to surround. I don't understand that last sentence. You argue against using more then two speaker-channels. And then you tell us you never meet anyone who prefered mono or stereo over surround? Love and peace, Arnold signature.asc Description: This is a digitally signed message part. ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On Wednesday 21 July 2010 23:27:59 Ralf Mardorf wrote: > On Wed, 2010-07-21 at 23:21 +0200, f...@kokkinizita.net wrote: > > And you fail regarding almost everything you write. If you want > > to pontificate about acoustics and psycho-acoustics then please > > study the subject before doing so. It will take some time and > > efforr but may help you to avoid making a fool of yourself. > I guess you make a fool of your self, perhaps not to Linux lists, but > indeed to professionals who have to do hard jobs all the day. Sorry for getting personal (you started it Ralf!), but: From what I have heard and seen from Fons' past and his present work both in terms of software and audio compared to what I could read from you, he is _far_ less likely to make a fool of himself anywhere in the audio/mixing/dsp/programming field. Neither in research nor in "hard daily work". Arnold signature.asc Description: This is a digitally signed message part. ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On Wed, Jul 21, 2010 at 10:07:10PM +0200, JohnLM wrote: > What's the thing about far and near fields? The rule pressure = 1 / distance is true only for theoretical point sources, and for real sources if the distance is much larger than the size of the zource. In the other case you are in the 'near field' where things can get quite complex. For some sounds you are almost always in the 'near' field e.g. a highway with many moving cars on it, the seashore, etc. These are essentially large line sources with many independent sound generators which blurr into a single sound, and in that case you'd get different relations, e.g. pressure = 1 / sqrt(distance). > On Wed, Jul 21, 2010 at 2:01 PM, wrote: > >An audio signal represents pressure variation as a function of > >time. Multiplying it by two will give 2 times the pressure, > >and 4 times the power. The subjective result is another matter. > > > Ummm... is it sound pressure or sound pressure level? Or it doesn't > matter? (are they equivalent?) The term 'sound pressure level' (SPL) usually refers to sound pressure measured in a standardized way. What you try to do is called spatialization. It involves modelling the directivity and motion of the sources and their interaction with the space they are in, and it can get arbitrarily complex. Software to do this in specialised cases (e.g. electronic music) exists. More general solutions and in particular practical systems (allowing complex and dynamic scenes) are still a research topic, e.g. at Barcelone Media. Ciao, -- FA There are three of them, and Alleline. ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On Wed, Jul 21, 2010 at 10:23:03PM +0100, Folderol wrote: > I remember when 2001 first came out, being totally astonished by the > sequence where the ape-man first uses a bone as a club. There was the > totally realistic effect of a gust of wind moving from the screen to the > rear of the cinema. I've no idea what system was in use, but it > certainly wasn't 2 channel stereo! 1968 IIRC Well before any Dolby-XYZ The 70mm version would have had 6 audio tracks, the 35mm one 4. Ciao, -- FA There are three of them, and Alleline. ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On 07/22/2010 09:52 AM, f...@kokkinizita.net wrote: On Wed, Jul 21, 2010 at 10:23:03PM +0100, Folderol wrote: I remember when 2001 first came out, being totally astonished by the sequence where the ape-man first uses a bone as a club. There was the totally realistic effect of a gust of wind moving from the screen to the rear of the cinema. I've no idea what system was in use, but it certainly wasn't 2 channel stereo! 1968 IIRC Well before any Dolby-XYZ The 70mm version would have had 6 audio tracks, the 35mm one 4. Ciao, Even Fantasia was recorded in multi channel and originally played like that throughout the world at theaters equipped for the experience. These days it is reduced to stereo or dolby surround which is a significant change from the original soundscape. -- Patrick Shirkey Boost Hardware Ltd ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On Thu, 2010-07-22 at 01:08 +0200, Arnold Krille wrote: > On Wednesday 21 July 2010 23:27:59 Ralf Mardorf wrote: > > On Wed, 2010-07-21 at 23:21 +0200, f...@kokkinizita.net wrote: > > > And you fail regarding almost everything you write. If you want > > > to pontificate about acoustics and psycho-acoustics then please > > > study the subject before doing so. It will take some time and > > > efforr but may help you to avoid making a fool of yourself. > > I guess you make a fool of your self, perhaps not to Linux lists, but > > indeed to professionals who have to do hard jobs all the day. > > Sorry for getting personal (you started it Ralf!), but: > > From what I have heard and seen from Fons' past and his present work both in > terms of software and audio compared to what I could read from you, he is > _far_ less likely to make a fool of himself anywhere in the > audio/mixing/dsp/programming field. Neither in research nor in "hard daily > work". Indeed. -- Fernando ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On 07/22/2010 12:58 PM, Fernando Lopez-Lezcano wrote: On Thu, 2010-07-22 at 01:08 +0200, Arnold Krille wrote: On Wednesday 21 July 2010 23:27:59 Ralf Mardorf wrote: On Wed, 2010-07-21 at 23:21 +0200, f...@kokkinizita.net wrote: And you fail regarding almost everything you write. If you want to pontificate about acoustics and psycho-acoustics then please study the subject before doing so. It will take some time and efforr but may help you to avoid making a fool of yourself. I guess you make a fool of your self, perhaps not to Linux lists, but indeed to professionals who have to do hard jobs all the day. Sorry for getting personal (you started it Ralf!), but: From what I have heard and seen from Fons' past and his present work both in terms of software and audio compared to what I could read from you, he is _far_ less likely to make a fool of himself anywhere in the audio/mixing/dsp/programming field. Neither in research nor in "hard daily work". Indeed. Oh yeah, Fons is wonderful and never makes a fool of himself. His shit smells sweet too! ;-P We need to erect a monument to the almighty, allwise and all powerful Fons. Nay, forsooth a religion shall be founded to worship at the feet of the 50 Foot Golden Standing Fons Statue. A giant Microphone and sound system shall also be erected in his honour and we shall sing in his name on imporatnt dates like when sent his first email and farted in melody ;-P Legends will be told and passed down through the generations and all practising members shall be required to install 30 point ambisonics in their living rooms as testiment to their faith. -- Patrick Shirkey Boost Hardware Ltd ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On Thursday 22 July 2010 05:38:22 Patrick Shirkey wrote: > On 07/22/2010 12:58 PM, Fernando Lopez-Lezcano wrote: > > On Thu, 2010-07-22 at 01:08 +0200, Arnold Krille wrote: > >> On Wednesday 21 July 2010 23:27:59 Ralf Mardorf wrote: > >>> On Wed, 2010-07-21 at 23:21 +0200, f...@kokkinizita.net wrote: > And you fail regarding almost everything you write. If you want > to pontificate about acoustics and psycho-acoustics then please > study the subject before doing so. It will take some time and > efforr but may help you to avoid making a fool of yourself. > >>> > >>> I guess you make a fool of your self, perhaps not to Linux lists, but > >>> indeed to professionals who have to do hard jobs all the day. > >> > >> Sorry for getting personal (you started it Ralf!), but: > >> From what I have heard and seen from Fons' past and his present work > >> both in > >> > >> terms of software and audio compared to what I could read from you, he > >> is _far_ less likely to make a fool of himself anywhere in the > >> audio/mixing/dsp/programming field. Neither in research nor in "hard > >> daily work". > > > > Indeed. > > Oh yeah, Fons is wonderful and never makes a fool of himself. His shit > smells sweet too! ;-P > > We need to erect a monument to the almighty, allwise and all powerful > Fons. Nay, forsooth a religion shall be founded to worship at the feet > of the 50 Foot Golden Standing Fons Statue. > > A giant Microphone and sound system shall also be erected in his honour > and we shall sing in his name on imporatnt dates like when sent his > first email and farted in melody ;-P > > Legends will be told and passed down through the generations and all > practising members shall be required to install 30 point ambisonics in > their living rooms as testiment to their faith. If it helps that Fons releases more of his wonderful software, then building a monument for him is okay ;-) Its not about glorifying Fons, but some people here have earned at least my respect for what they do and what they say. Arnold signature.asc Description: This is a digitally signed message part. ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On 21 July 2010 22:18, Ralf Mardorf wrote: > Btw. sometimes I do fail too, so I don't insist that I'm not mistaken, > to the contrary, it would be a win for me too, if I should fail with my > opinion. Basically, just as long as you post twenty thousand emails to every goddamn linux audio related mailing list per hour you're happy. ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On 2010.07.22. 1:30, f...@kokkinizita.net wrote: On Wed, Jul 21, 2010 at 10:07:10PM +0200, JohnLM wrote: What's the thing about far and near fields? The rule pressure = 1 / distance is true only for theoretical point sources, and for real sources if the distance is much larger than the size of the zource. In the other case you are in the 'near field' where things can get quite complex. For some sounds you are almost always in the 'near' field e.g. a highway with many moving cars on it, the seashore, etc. These are essentially large line sources with many independent sound generators which blurr into a single sound, and in that case you'd get different relations, e.g. pressure = 1 / sqrt(distance). On Wed, Jul 21, 2010 at 2:01 PM, wrote: An audio signal represents pressure variation as a function of time. Multiplying it by two will give 2 times the pressure, and 4 times the power. The subjective result is another matter. Ummm... is it sound pressure or sound pressure level? Or it doesn't matter? (are they equivalent?) The term 'sound pressure level' (SPL) usually refers to sound pressure measured in a standardized way. What you try to do is called spatialization. It involves modelling the directivity and motion of the sources and their interaction with the space they are in, and it can get arbitrarily complex. Software to do this in specialised cases (e.g. electronic music) exists. More general solutions and in particular practical systems (allowing complex and dynamic scenes) are still a research topic, e.g. at Barcelone Media. Ciao, I may have bitten more than I can chew on. :) Currently I seek to make "stupid" solution. Something like the way every decent game engine does it. Except my solution is going to be non-realtime and not (sound) hardware dependent. I reckon something like this already exist in FOSS, but I haven't been able to find anything (I have no time examining code of every other audio project out there). Thanks for the info. Good to know I'm heading the right way. Indeed 'near field' sound sources were ones I never actually gave much thought on their implementation in software. This will go next on my TODO list. Regards, John ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On Wed, 2010-07-21 at 17:45 -0400, Paul Davis wrote: > if that won't work for you, then perhaps you might want to visit any > of the theaters outfitted by these guys: > http://www.iosono-sound.com/references/installations/ The nearest to Oberhausen is http://www.odysseum.de/, unfortunately it's expensive to get from Oberhausen to Köln, but it might be feasible to get there. If the 3D sound system should be good, I fear that still the kind of production isn't something that will be able to demonstrate it, http://www.odysseum.de/id-3d-filme.html?! Reputable would be the Hochschule für Musik Detmold, but it's to far away for my purse and perhaps it won't be easy for a guest to be allowed to listen to a performance, because it's a school. The picture to the quote „The best listening position is where I sit in a live performance. With IOSONO you can put the entire audience in my lap.“ Herbie Hancock, doesn't look like 5.1 or something similar: http://www.iosono-sound.com/common/files/header/home1_tresor.jpg System requirements Operating System: Windows XP Professional SP2, Windows 7 Host application: Steinberg`s Nuendo 4 (Nuendo dongle required) Processor: Dual Core 2.4 Ghz Graphic board: Open-GL support recommended Sound card: 6 Output Channels or more recommended Display: Resolution 1280 x 1024 Px, Dual Display recommended I'm interested to listen to a performance. Cheers! Ralf ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On Thu, Jul 22, 2010 at 7:44 AM, Ralf Mardorf wrote: > The picture to the quote „The best listening position is where I sit in > a live performance. With IOSONO you can put the entire audience in my > lap.“ Herbie Hancock, doesn't look like 5.1 or something similar: > http://www.iosono-sound.com/common/files/header/home1_tresor.jpg this is about *audio*. what is looks like tells you almost nothing. in addition, you don't ned anything fancy to listen to B-format recordings, and one of the major reasons for that is fons' open source decoder that will allow you to listen to them with any jack-enabled audio player and your existing equipment. you also don't need any particular speaker setup, although clearly one of the points of ambisonics is that (up to a limit) adding more speakers enables a more accurate recreation of sound placement within 3D to be achieved. ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On Thu, 2010-07-22 at 01:04 +0200, Arnold Krille wrote: > We are not talking about 5.1 or 7.1 here. These suck big time. > > We are talking about ambisonics vs. binaurals vs. simple stereo here! Ok, I noticed this. Fon's AmbDec is the player for the files from http://www.ambisonia.com/?! I guess a friend who lives near to my home has at least 8 outputs for an Envy24 sound card and at least a JBL 5.1 setup, so the 5.1 speakers could be used for a minimalist ambisonics. > > > A lot of people, even a lot of those who you respect, tried it and I > > never meed someone who preferred mono or stereo to surround. > > I don't understand that last sentence. You argue against using more then two > speaker-channels. And then you tell us you never meet anyone who prefered > mono > or stereo over surround? Bad sentence construction don by me. Cheers! Ralf ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On Wed, Jul 21, 2010 at 11:38 PM, Patrick Shirkey wrote: > Oh yeah, Fons is wonderful and never makes a fool of himself. His shit > smells sweet too! ;-P this was completely pointless. and offensive. and rude. ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
Hi, On Thursday 22 July 2010 14:01:36 Ralf Mardorf wrote: > On Thu, 2010-07-22 at 01:04 +0200, Arnold Krille wrote: > > We are not talking about 5.1 or 7.1 here. These suck big time. > > We are talking about ambisonics vs. binaurals vs. simple stereo here! > Ok, I noticed this. > Fon's AmbDec is the player for the files from > http://www.ambisonia.com/?! No. Decoder != Player. Please read the (very fine!) manual to ambdec. And then use any jack-aware player to play the files. I use mplayer and that works great. > I guess a friend who lives near to my home has at least 8 outputs for an > Envy24 sound card and at least a JBL 5.1 setup, so the 5.1 speakers > could be used for a minimalist ambisonics. Keep in mind that 5.1 systems are only a poor substitute for ambisonics set- ups. Even when using jbl-speakers, the set up is still different resulting from the different use cases. 5.1 is practically stereo. Its one mono for the voices (called center), one stereo for music and ambient (called front) and one stereo for special effects (called rear). [Forget about that extra channel for lfe which tries to be smarter then the user.] Ambisonics is really every channel with the same priority and use-case. It will not matter whether you use the set up with "front" at positiv-x direction or 130° rotated around the z axis and 30° rotated around the x axis (when using a full 3D rig). It will sound all the same. And the speakers in the room have to be set up for this. Also the speakers are all supposed to be equally away from the listener for best performance, with 5.1 the rear is supposed to be much nearer to the listeners than the front and center. You see ambisonics and 5.1 are different things. Because of that your (and my) aversion against 5.1 can not be held against ambisonics. And because of that a 5.1 set-up is only of limited use for ambisonics re-production. Have fun, Arnold signature.asc Description: This is a digitally signed message part. ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On Thu, Jul 22, 2010 at 08:11:21AM -0400, Paul Davis wrote: > On Wed, Jul 21, 2010 at 11:38 PM, Patrick Shirkey > wrote: > > > Oh yeah, Fons is wonderful and never makes a fool of himself. His shit > > smells sweet too! ;-P > > this was completely pointless. and offensive. and rude. It depends mostly on the type of yesterday evening's pizza I guess. Ciao, -- FA There are three of them, and Alleline. ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On Thu, Jul 22, 2010 at 01:38:22PM +1000, Patrick Shirkey wrote: > A giant Microphone and sound system shall also be erected in his > honour and we shall sing in his name on imporatnt dates like when > sent his first email and farted in melody ;-P Too much. just my birthday will do, it's the first of april. You may think I've been to harsh to R.M., but one has to draw a line somewhere. A few weeks ago two religious fundementalists (don't know which denomination) rang at my gate to discuss the fallacy of Evolution. One of them asked "Did your grandpa look like this ?", showing a picture of an ape. I responded "No, not at all. But let me ask you, did _your_ grandfathers _think_ like apes ?" - "No" - "So why do _you_ ?". And that ended our little discussion. Stating that we have only two ears and that consequently any audio system reproducing 3D would require direct injection into our brains is about at the same level of ignorance. Ciao, -- FA There are three of them, and Alleline. ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On Thu, Jul 22, 2010 at 12:48 PM, Paul Davis wrote: > you don't ned anything fancy to listen to B-format > recordings, and one of the major reasons for that is fons' open source > decoder that will allow you to listen to them with any jack-enabled > audio player and your existing equipment. Question that just occurred to me. I'm very ignorant about spatial audio, and although I'm sure several of my colleagues could tell me this, I thought it might be sort of on-topic here. Is it possible, or easy, or sensible, or worthwhile, to reduce a B-format recording into stereo in multiple different ways in order to achieve different subjective "listener position" results when using headphones? Chris ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On Thu, Jul 22, 2010 at 10:29 AM, Chris Cannam wrote: > Question that just occurred to me. I'm very ignorant about spatial > audio, and although I'm sure several of my colleagues could tell me > this, I thought it might be sort of on-topic here. Is it possible, or > easy, or sensible, or worthwhile, to reduce a B-format recording into > stereo in multiple different ways in order to achieve different > subjective "listener position" results when using headphones? my limited understanding is this: the B-format data encodes the source position relative to some defined point in space. the decoder can map the "origin" used to define the positional space however it wants to. whether or not any decoders actually offer any control over this is another matter. ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On Thursday 22 July 2010 16:29:01 Chris Cannam wrote: > On Thu, Jul 22, 2010 at 12:48 PM, Paul Davis wrote: > > you don't ned anything fancy to listen to B-format > > recordings, and one of the major reasons for that is fons' open source > > decoder that will allow you to listen to them with any jack-enabled > > audio player and your existing equipment. > > Question that just occurred to me. I'm very ignorant about spatial > audio, and although I'm sure several of my colleagues could tell me > this, I thought it might be sort of on-topic here. Is it possible, or > easy, or sensible, or worthwhile, to reduce a B-format recording into > stereo in multiple different ways in order to achieve different > subjective "listener position" results when using headphones? It makes sense to reduce B-format to stereo. But the target is important, if you aim at headphones, there are decoders that create an binaural signal. If normal stereo-systems are the target, you will do a decoding similar to any ambisonics setup but only use two speakers in the correct stereo positions and decode to file... The headphone-version gives more of the ambisonics feeling, but the normal stereo signal also benefits from the recording done in ambisonics. Have fun, Arnold signature.asc Description: This is a digitally signed message part. ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On Thu, Jul 22, 2010 at 10:35:15AM -0400, Paul Davis wrote: > On Thu, Jul 22, 2010 at 10:29 AM, Chris Cannam > wrote: > > Question that just occurred to me. I'm very ignorant about spatial > > audio, and although I'm sure several of my colleagues could tell me > > this, I thought it might be sort of on-topic here. Is it possible, or > > easy, or sensible, or worthwhile, to reduce a B-format recording into > > stereo in multiple different ways in order to achieve different > > subjective "listener position" results when using headphones? > > my limited understanding is this: the B-format data encodes the > source position relative to some defined point in space. the decoder > can map the "origin" used to define the positional space however it > wants to. whether or not any decoders actually offer any control over > this is another matter. The first order B-format consists of four signals: W: equivalent to an 'omni' microphone, X,Y,Z: equivalent to figure-of-eight microphones pointing forward/back, left/right, and up/ down respectively. Combining these you can synthesize any type of first order mic, going from omni, over subcardioid, cardioid, hypercardioid to bidirectional, and in any direction. So starting with B-format, you can convert it to stereo using e.g. two figure-of-eights at 90 degrees (Blumlein) or two cardioids at 110 degrees (ORTF), etc. The type of mics and their angle will determine the direct to reverberation ratio to some extent, and therefor the apparent placement of the stereo mic. Such a 'virtual stereo mic' is part of Tetraproc, and there's also a Ladspa plugin doing this. The latter has some problems in Ardour as it has 4 ins and 2 outs, and Ardour get confused by this and will (IIRC) copy inputs 3 and 4 to the outputs while it shouldn't do that. Another way is to decode to a number of speaker signals and then use HRIR (head-related impulse responses) to convert to binaural. Ambdec + Jconvolver (or just Jconvolver with some extra prepartion) can do this. Ciao, -- FA There are three of them, and Alleline. ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On Thu, 2010-07-22 at 14:01 +0200, Ralf Mardorf wrote: > On Thu, 2010-07-22 at 01:04 +0200, Arnold Krille wrote: > > We are not talking about 5.1 or 7.1 here. These suck big time. > > > > We are talking about ambisonics vs. binaurals vs. simple stereo here! > > Ok, I noticed this. > > Fon's AmbDec is the player for the files from > http://www.ambisonia.com/?! > > I guess a friend who lives near to my home has at least 8 outputs for an > Envy24 sound card and at least a JBL 5.1 setup, so the 5.1 speakers > could be used for a minimalist ambisonics. Yes. Fons ships an ambdec configuration for playing in a 5.1 setup (it is not optimal because the back speakers in a 5.1 setup are too far apart but it works - I use it at home). Of course it assumes that the 5.1 setup is correct. This link has a diagram of the speaker angles: http://de.wikipedia.org/wiki/5.1 -- Fernando ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On Thursday, July 22, 2010 01:07:57 pm f...@kokkinizita.net did opine: > On Thu, Jul 22, 2010 at 10:35:15AM -0400, Paul Davis wrote: > > On Thu, Jul 22, 2010 at 10:29 AM, Chris Cannam > > > > wrote: > > > Question that just occurred to me. I'm very ignorant about spatial > > > audio, and although I'm sure several of my colleagues could tell me > > > this, I thought it might be sort of on-topic here. Is it possible, > > > or easy, or sensible, or worthwhile, to reduce a B-format recording > > > into stereo in multiple different ways in order to achieve > > > different subjective "listener position" results when using > > > headphones? > > > > my limited understanding is this: the B-format data encodes the > > source position relative to some defined point in space. the decoder > > can map the "origin" used to define the positional space however it > > wants to. whether or not any decoders actually offer any control over > > this is another matter. > > The first order B-format consists of four signals: > > W: equivalent to an 'omni' microphone, > X,Y,Z: equivalent to figure-of-eight microphones > pointing forward/back, left/right, and up/ > down respectively. And interesting scenario, Fons. But it leads this simple minded broadcast engineer with 45 years experience to ask a question. 1. How are the signals brought into phase such that electronically, all mic ribbons or diaphragms seem to occupy the same space, just facing in different directions? If this is not addressed, then this will lead to some interesting comb filter effects if the signals are not kept from mixing, which they will of course do in the ear. Granted, the PV of sound in normal air would require separations of inches till the stuff above high C comes into play, but at the snares and cymbals frequencies, I would have to assume some coloration of the sound from this effect alone. And of course the same concern comes into play at the speakers since they are generally placed around the listener which in no way approximates the nearly single point reception these mics will hear. In my own mind, the placement of a PZ microphone in each of the places one would place the playback speakers would seem to be a superior method, at least for a listener sitting in the nominal center, who will be so overwhelmed by (supposedly not important sonically we are told) the phasing errors that he cannot single out a single largest cause for the lack of realism. In my history of electronic repairs for a living over the last 60+ years, one instance of truly hair raising realism took place when I was about 21, and working one of the service benches at Woodburn Sound in Iowa City IA, USA. I had bought some car parts at noon, and when I left about 6 for dinner, I forgot & left them on the corner of the bench. Having a key to the back door I let myself into the back door about 8, which was pretty dark by then as only one 25 watt bulb out in the display area was on, and half way to the door to my bench area & right in the door to the front, display room, the Dukes of Dixieland marched by, going right over me. It seems that Woody and Saul Marantz were out in front, had pulled a 2nd JBL Hartzfield speaker out of Saul's econoline van, setting it just inside the front door opposite to ours in the other front corner of the display floor, along with a Berlant/Concertone tape deck capable of running at 15 and 30 IPS. And the tape was the master that had cut the Dukes then current hit record, running at 30 ips. SNR was a good 70+ db, and there was no tape hiss audible unless you walked directly in front of the JBL 075 ring radiator tweeters that had been added to both our Hartzfield and to the one Saul was carrying around. No tone controls, and only a 30 watt Marantz stereo amp., those Hartzfields were then, and may be yet, the most efficient speakers ever made, never used more than 3 or 4 watts/channel to get SPL's that would have done Joshua's trumpets at Jericho proud. Truly a total immersion in the sound, from about 35hz to nearly 30khz. Those tweeters could do a fairly good job of reproducing a 25khz square wave. It took till I had been introduced to Saul Marantz and shook hands, and for that tape (on 14" NAB reels) to run out before the hair on the back of my neck was truly relaxed. Saul it turned out was an endless source of technical knowledge sprinkled with BTDT stories. And needless to say, I did not manage to get that hydromatic transmission I had just stick shifted back together till a day later. Yeah, I'm a JOAT. :) -- Cheers, Gene "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) The cost of living is going up, and the chance of living is going down. ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaud
Re: [LAD] Attenuation of sounds in 3D space
On Thu, 2010-07-22 at 10:52 -0700, Fernando Lopez-Lezcano wrote:
> On Thu, 2010-07-22 at 14:01 +0200, Ralf Mardorf wrote:
> > On Thu, 2010-07-22 at 01:04 +0200, Arnold Krille wrote:
> > > We are not talking about 5.1 or 7.1 here. These suck big time.
> > >
> > > We are talking about ambisonics vs. binaurals vs. simple stereo here!
> >
> > Ok, I noticed this.
> >
> > Fon's AmbDec is the player for the files from
> > http://www.ambisonia.com/?!
> >
> > I guess a friend who lives near to my home has at least 8 outputs for an
> > Envy24 sound card and at least a JBL 5.1 setup, so the 5.1 speakers
> > could be used for a minimalist ambisonics.
>
> Yes. Fons ships an ambdec configuration for playing in a 5.1 setup (it
> is not optimal because the back speakers in a 5.1 setup are too far
> apart but it works - I use it at home). Of course it assumes that the
> 5.1 setup is correct. This link has a diagram of the speaker angles:
>
> http://de.wikipedia.org/wiki/5.1
>
> -- Fernando
The speakers of the 5.1 system should just be used, because they are 5
of the same type and because there are equal amps for the speakers.
There's no need to keep
http://upload.wikimedia.org/wikipedia/de/thumb/4/4e/ITUKreis_Ruhnke.jpg/300px-ITUKreis_Ruhnke.jpg,
if the speakers should really be placed correctly for 5.1 at the friends
living room at the moment.
If possible I would prefer to replace them in a way that's good for
ambisonics.
From: Arnold Krille
To: linux-audio-dev@lists.linuxaudio.org
Subject: Re: [LAD] Attenuation of sounds in 3D space
Date: Thu, 22 Jul 2010 14:51:00 +0200
[snip]
Ambisonics is really every channel with the same priority and use-case.
It
will not matter whether you use the set up with "front" at positiv-x
direction
or 130° rotated around the z axis and 30° rotated around the x axis
(when
using a full 3D rig). It will sound all the same. And the speakers in
the room
have to be set up for this.
Also the speakers are all supposed to be equally away from the listener
for
best performance
[snip]
IIUC 4 speakers could be set up in a quadrate with "front" at positiv-x
direction and the listener has to be in the middle of the quadrate.
Maybe there will be 8 similar speakers and amps, but regarding to the
sound card the limit is 8 channels. I guess somewhere on the ambisonics
website there will be some text and graphic about such setups.
- Ralf
___
Linux-audio-dev mailing list
Linux-audio-dev@lists.linuxaudio.org
http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On Thu, 2010-07-22 at 14:15 -0400, Gene Heskett wrote: > On Thursday, July 22, 2010 01:07:57 pm f...@kokkinizita.net did opine: > > > On Thu, Jul 22, 2010 at 10:35:15AM -0400, Paul Davis wrote: > > > On Thu, Jul 22, 2010 at 10:29 AM, Chris Cannam > > > > > > wrote: > > > > Question that just occurred to me. I'm very ignorant about spatial > > > > audio, and although I'm sure several of my colleagues could tell me > > > > this, I thought it might be sort of on-topic here. Is it possible, > > > > or easy, or sensible, or worthwhile, to reduce a B-format recording > > > > into stereo in multiple different ways in order to achieve > > > > different subjective "listener position" results when using > > > > headphones? > > > > > > my limited understanding is this: the B-format data encodes the > > > source position relative to some defined point in space. the decoder > > > can map the "origin" used to define the positional space however it > > > wants to. whether or not any decoders actually offer any control over > > > this is another matter. > > > > The first order B-format consists of four signals: > > > > W: equivalent to an 'omni' microphone, > > X,Y,Z: equivalent to figure-of-eight microphones > > pointing forward/back, left/right, and up/ > > down respectively. > > And interesting scenario, Fons. But it leads this simple minded broadcast > engineer with 45 years experience to ask a question. > > 1. How are the signals brought into phase such that electronically, all mic > ribbons or diaphragms seem to occupy the same space, just facing in > different directions? > > If this is not addressed, then this will lead to some interesting comb > filter effects if the signals are not kept from mixing, which they will of > course do in the ear. > > Granted, the PV of sound in normal air would require separations of inches > till the stuff above high C comes into play, but at the snares and cymbals > frequencies, I would have to assume some coloration of the sound from this > effect alone. And of course the same concern comes into play at the > speakers since they are generally placed around the listener which in no > way approximates the nearly single point reception these mics will hear. > > In my own mind, the placement of a PZ microphone in each of the places one > would place the playback speakers would seem to be a superior method, at > least for a listener sitting in the nominal center, who will be so > overwhelmed by (supposedly not important sonically we are told) the phasing > errors that he cannot single out a single largest cause for the lack of > realism. > > In my history of electronic repairs for a living over the last 60+ years, > one instance of truly hair raising realism took place when I was about 21, > and working one of the service benches at Woodburn Sound in Iowa City IA, > USA. I had bought some car parts at noon, and when I left about 6 for > dinner, I forgot & left them on the corner of the bench. Having a key to > the back door I let myself into the back door about 8, which was pretty > dark by then as only one 25 watt bulb out in the display area was on, and > half way to the door to my bench area & right in the door to the front, > display room, the Dukes of Dixieland marched by, going right over me. It > seems that Woody and Saul Marantz were out in front, had pulled a 2nd JBL > Hartzfield speaker out of Saul's econoline van, setting it just inside the > front door opposite to ours in the other front corner of the display floor, > along with a Berlant/Concertone tape deck capable of running at 15 and 30 > IPS. And the tape was the master that had cut the Dukes then current hit > record, running at 30 ips. SNR was a good 70+ db, and there was no tape > hiss audible unless you walked directly in front of the JBL 075 ring > radiator tweeters that had been added to both our Hartzfield and to the one > Saul was carrying around. No tone controls, and only a 30 watt Marantz > stereo amp., those Hartzfields were then, and may be yet, the most efficient > speakers ever made, never used more than 3 or 4 watts/channel to get SPL's > that would have done Joshua's trumpets at Jericho proud. > > Truly a total immersion in the sound, from about 35hz to nearly 30khz. > Those tweeters could do a fairly good job of reproducing a 25khz square > wave. > > It took till I had been introduced to Saul Marantz and shook hands, and for > that tape (on 14" NAB reels) to run out before the hair on the back of my > neck was truly relaxed. Saul it turned out was an endless source of > technical knowledge sprinkled with BTDT stories. And needless to say, I > did not manage to get that hydromatic transmission I had just stick shifted > back together till a day later. Yeah, I'm a JOAT. :) > As an ape (of course I'm an ape like every human is an ape) and troll (I don't see myself as a troll) I suspect phasing too, that's why I
Re: [LAD] Attenuation of sounds in 3D space
On Thu, 2010-07-22 at 20:22 +0200, Ralf Mardorf wrote: > On Thu, 2010-07-22 at 10:52 -0700, Fernando Lopez-Lezcano wrote: > > On Thu, 2010-07-22 at 14:01 +0200, Ralf Mardorf wrote: > > > On Thu, 2010-07-22 at 01:04 +0200, Arnold Krille wrote: > > > > We are not talking about 5.1 or 7.1 here. These suck big time. > > > > > > > > We are talking about ambisonics vs. binaurals vs. simple stereo here! > > > > > > Ok, I noticed this. > > > > > > Fon's AmbDec is the player for the files from > > > http://www.ambisonia.com/?! > > > > > > I guess a friend who lives near to my home has at least 8 outputs for an > > > Envy24 sound card and at least a JBL 5.1 setup, so the 5.1 speakers > > > could be used for a minimalist ambisonics. > > > > Yes. Fons ships an ambdec configuration for playing in a 5.1 setup (it > > is not optimal because the back speakers in a 5.1 setup are too far > > apart but it works - I use it at home). Of course it assumes that the > > 5.1 setup is correct. This link has a diagram of the speaker angles: > > > > http://de.wikipedia.org/wiki/5.1 > > > The speakers of the 5.1 system should just be used, because they are 5 > of the same type and because there are equal amps for the speakers. > There's no need to keep > http://upload.wikimedia.org/wikipedia/de/thumb/4/4e/ITUKreis_Ruhnke.jpg/300px-ITUKreis_Ruhnke.jpg, > if the speakers should really be placed correctly for 5.1 at the friends > living room at the moment. I'm not sure I understand. The 5.1 ambisonics decoder in Ambdec can decode to that arrangement and it is pretty good. You could try that before moving the speakers around. > If possible I would prefer to replace them in a way that's good for > ambisonics. > ... > IIUC 4 speakers could be set up in a quadrate with "front" at positiv-x > direction and the listener has to be in the middle of the quadrate. Yes, you could move them into a square, use only four and use the square decoder. A 5.1 setup can be used to play up to second order ambisonics, a 4 channel square can only play first order ambisonics. Most of the recordings in ambisonia.com are first order (but I think there are a few higher order as well). See this for another example of ambisonics at home: http://stackingdwarves.net/public_stuff/linux_audio/ambi_at_home/joern_nettingsmeier-ambisonics_at_home.pdf -- Fernando > Maybe there will be 8 similar speakers and amps, but regarding to the > sound card the limit is 8 channels. I guess somewhere on the ambisonics > website there will be some text and graphic about such setups. ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On 07/22/2010 05:02 PM, f...@kokkinizita.net wrote: Such a 'virtual stereo mic' is part of Tetraproc, and there's also a Ladspa plugin doing this. The latter has some problems in Ardour as it has 4 ins and 2 outs, and Ardour get confused by this and will (IIRC) copy inputs 3 and 4 to the outputs while it shouldn't do that. ardour always does that. it's consistent (but wrong imho) and nothing to do with the vmic plugin. when you use the plugin in a bus with 4 ins and 2 outs, everything works as expected. if you find such busses confusing, an alternative is to use a 4 in 4 out bus and leave outputs 3 and 4 unconnected. ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On 07/22/2010 08:15 PM, Gene Heskett wrote: 1. How are the signals brought into phase such that electronically, all mic ribbons or diaphragms seem to occupy the same space, just facing in different directions? well, you can't do that :) two approaches: if you only care for horizontal surround (and there is no significant z axis content), you can stack an omni and two fig8s on top of one another, so that they are in phase for signals arriving along the horizontal plane. this is often called the nimbus-halliday array, after the guy that introduced it at nimbus records. sounds very good, but no height. if you do want height, place 4 sub-cards or cardiods as close together as possible, arranged on the faces of a tetrahedron. then with some clever filtering, you can get very good results, and the comb filtering at hf can be worked around with a slight treble boost. comb filtering at hf looks worse than it sounds, usually. And of course the same concern comes into play at the speakers since they are generally placed around the listener which in no way approximates the nearly single point reception these mics will hear. that's not the point. the idea is this: you measure the soundfield in one spot, and you aim to reproduce it in this one spot only (that's the maths). so the speakers should be really really close together. the good thing is: it also works when the speakers are far apart, which means we get room for listeners :) the interesting aspect of first-order ambisonics is not how it works (it only works in a point volume, which is not terribly useful), but how gracefully it fails outside this volume. In my own mind, the placement of a PZ microphone in each of the places one would place the playback speakers would seem to be a superior method, at least for a listener sitting in the nominal center, who will be so overwhelmed by (supposedly not important sonically we are told) the phasing errors that he cannot single out a single largest cause for the lack of realism. it might seem so, but in practice it does not really work. say you have a regular hexagon of microphones, with a radius of 2m. assume that a singer is standing at the "north" mike. sound reaches this mike instantaneously. it takes about 12ms to reach the south mike. that is a comb filter that reaches way down where it makes the sound tinny, unpleasant, and worst of all, unrepairable. and consider what the effect during playback would be: loud, correct sound from north speaker after 6ms, bogus echo from south speaker after 18ms, combining into coloration, giving a wrong spatial cue of a back wall that isn't there, yet arriving too soon for the brain to be able to separate it as a bogus event and throw it away. the fun thing is, if you had several thousand microphones (and speakers), the results would be excellent. but before shouldering the expenses, you might be tempted to cut some corners. ambisonics is a very usable shortcut imho. ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On 07/22/2010 08:42 PM, Ralf Mardorf wrote: As an ape (of course I'm an ape like every human is an ape) and troll (I don't see myself as a troll) I suspect phasing too, that's why I overstated argued with the next generation Cochlea-Implant, or needles in the brain. that is a bogus statement. phasing happens in the brain as well. just put on your favourite pair of headphones and wire one side out-of-phase. instant nausea. (of course, if you keep it on for a few days, your brain will adapt - presto: you'll be hurling all over the real world when you finally put them down.) Visual 3D, by a surround projection + 3D glasses isn't perfect, but there is just one picture and not several pictures that needs to be phase synced in the eye. Perhaps a week analogy. a terribly chosen analogy indeed. since when do the eyes care what phase an incoming photon is? unless you're staring into a laser, each photon will have totally random phase. next error: there *are* two images, and they do need to be synced. phase is irrelevant, though. When having 4 or 8 or more speakers I fear phasing at the position of the ears. But perhaps it isn't that much. I'll try to listen to ambisoncs :). you can get terrible phasing, and not just in the center, but pretty much everywhere. that's why some people stagger the timings of the loudspeakers a bit, to smear out the phasing until it is more or less masked by the content. but it should be noted that stereo has the very same problem. now if method A produces a 60° soundstage with phasing at N units of obnoxiousness, a method that produces 360° surround is entitled to 6N UoO phasing. in practice, ambisonics does better than this, but there is no denying the issue. one thing that often gets overlooked: people have learned to accept stereo (or, in some circles, 5.1) as the gold standard, and its shortcomings have grown into desired features. it's very hard to compete with a method that does a few things very well and doesn't even try to reproduce most of the auditory cues of, say, a live experience. the main ingredient that makes any sound reproduction system sound good is your brain. the trick is to nudge it into sympathy with carefully chosen cues. ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On Fri, 2010-07-23 at 01:09 +0200, Jörn Nettingsmeier wrote: > On 07/22/2010 08:42 PM, Ralf Mardorf wrote: > > > As an ape (of course I'm an ape like every human is an ape) and troll (I > > don't see myself as a troll) I suspect phasing too, that's why I > > overstated argued with the next generation Cochlea-Implant, or needles > > in the brain. > > that is a bogus statement. phasing happens in the brain as well. just > put on your favourite pair of headphones and wire one side out-of-phase. > instant nausea. (of course, if you keep it on for a few days, your brain > will adapt - presto: you'll be hurling all over the real world when you > finally put them down.) > > > Visual 3D, by a surround projection + 3D glasses isn't perfect, but > > there is just one picture and not several pictures that needs to be > > phase synced in the eye. Perhaps a week analogy. > > a terribly chosen analogy indeed. since when do the eyes care what phase > an incoming photon is? unless you're staring into a laser, each photon > will have totally random phase. > next error: there *are* two images, and they do need to be synced. phase > is irrelevant, though. That's the problem with this analogy. We have two eyes and ears, but most people have better trained eyes, so most people 'see' differences, but less people 'hear' differences. > > > When having 4 or 8 or more speakers I fear phasing at the position of > > the ears. But perhaps it isn't that much. I'll try to listen to > > ambisoncs :). > > you can get terrible phasing, and not just in the center, but pretty > much everywhere. that's why some people stagger the timings of the > loudspeakers a bit, to smear out the phasing until it is more or less > masked by the content. > but it should be noted that stereo has the very same problem. As I mentioned before, it's hard to do a good stereo mix, even when the speakers are perfectly set up. When you play music on radio, you need to check the phases of the recordings, because there are a lot of bad recordings. I guess it becomes harder the more channels you need to control. > now if > method A produces a 60° soundstage with phasing at N units of > obnoxiousness, a method that produces 360° surround is entitled to 6N > UoO phasing. in practice, ambisonics does better than this, but there is > no denying the issue. > one thing that often gets overlooked: people have learned to accept > stereo (or, in some circles, 5.1) as the gold standard, and its > shortcomings have grown into desired features. it's very hard to compete > with a method that does a few things very well and doesn't even try to > reproduce most of the auditory cues of, say, a live experience. Correct, I like stereo, I don't like 5.1 and indeed stereo is very limited, but with some training it's good to handle. If ambisonics shouldn't have the disadvantages of 5.1 I might like it. It's funny, regarding to the German Wiki ambisonics is as old as I'm. > the main ingredient that makes any sound reproduction system sound good > is your brain. the trick is to nudge it into sympathy with carefully > chosen cues. Btw. I 'try' to do stereo mixes that do sound mono as near as possible to the stereo mix and mono could be two channels as one or just one of the two channels. So I limit stereo to a special functionality, but don't use all capabilities. This could be called 'broadcasting behaviour'. I know that I need to break this habit for surround sound, but when listening and unfortunately working with 5.1, I didn't like it. Btw. even some consumers don't like 5.1, but perhaps because they set up the speakers completely bad. IIUC they hardly could set up the speakers completely bad, if they would use ambisonics. IIUC for large rooms there are many speakers needed, perhaps this is the reason that shit like 5.1, Dolby surround, Dolby stereo is common. OT: For film on cord Dolby stereo anyway is nice for stereo, without Dolby there's hardcore wow and flutter ... hm, regarding to wiki it's called dolby digital, doesn't matter German filmmakers usually can't pay for Dolby. Thanx for the information :) Ralf ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On Fri, 2010-07-23 at 08:51 +0200, Ralf Mardorf wrote: > On Fri, 2010-07-23 at 01:09 +0200, Jörn Nettingsmeier wrote: > > On 07/22/2010 08:42 PM, Ralf Mardorf wrote: > > > > > As an ape (of course I'm an ape like every human is an ape) and troll (I > > > don't see myself as a troll) I suspect phasing too, that's why I > > > overstated argued with the next generation Cochlea-Implant, or needles > > > in the brain. > > > > that is a bogus statement. phasing happens in the brain as well. just > > put on your favourite pair of headphones and wire one side out-of-phase. > > instant nausea. (of course, if you keep it on for a few days, your brain > > will adapt - presto: you'll be hurling all over the real world when you > > finally put them down.) > > > > > Visual 3D, by a surround projection + 3D glasses isn't perfect, but > > > there is just one picture and not several pictures that needs to be > > > phase synced in the eye. Perhaps a week analogy. > > > > a terribly chosen analogy indeed. since when do the eyes care what phase > > an incoming photon is? unless you're staring into a laser, each photon > > will have totally random phase. > > next error: there *are* two images, and they do need to be synced. phase > > is irrelevant, though. > > That's the problem with this analogy. We have two eyes and ears, but > most people have better trained eyes, so most people 'see' differences, > but less people 'hear' differences. > > > > > > When having 4 or 8 or more speakers I fear phasing at the position of > > > the ears. But perhaps it isn't that much. I'll try to listen to > > > ambisoncs :). > > > > you can get terrible phasing, and not just in the center, but pretty > > much everywhere. that's why some people stagger the timings of the > > loudspeakers a bit, to smear out the phasing until it is more or less > > masked by the content. > > but it should be noted that stereo has the very same problem. > > As I mentioned before, it's hard to do a good stereo mix, even when the > speakers are perfectly set up. When you play music on radio, you need to > check the phases of the recordings, because there are a lot of bad > recordings. I guess it becomes harder the more channels you need to > control. PS: Not only because of the position of the speakers, but started with the recoding, resp. master mix, that's why ... > > > now if > > method A produces a 60° soundstage with phasing at N units of > > obnoxiousness, a method that produces 360° surround is entitled to 6N > > UoO phasing. in practice, ambisonics does better than this, but there is > > no denying the issue. > > one thing that often gets overlooked: people have learned to accept > > stereo (or, in some circles, 5.1) as the gold standard, and its > > shortcomings have grown into desired features. it's very hard to compete > > with a method that does a few things very well and doesn't even try to > > reproduce most of the auditory cues of, say, a live experience. > > Correct, I like stereo, I don't like 5.1 and indeed stereo is very > limited, but with some training it's good to handle. > If ambisonics shouldn't have the disadvantages of 5.1 I might like it. > It's funny, regarding to the German Wiki ambisonics is as old as I'm. > > > the main ingredient that makes any sound reproduction system sound good > > is your brain. the trick is to nudge it into sympathy with carefully > > chosen cues. ...: > Btw. I 'try' to do stereo mixes that do sound mono as near as possible > to the stereo mix and mono could be two channels as one or just one of > the two channels. So I limit stereo to a special functionality, but > don't use all capabilities. This could be called 'broadcasting > behaviour'. I know that I need to break this habit for surround sound, > but when listening and unfortunately working with 5.1, I didn't like it. > > Btw. even some consumers don't like 5.1, but perhaps because they set up > the speakers completely bad. IIUC they hardly could set up the speakers > completely bad, if they would use ambisonics. IIUC for large rooms there > are many speakers needed, perhaps this is the reason that shit like 5.1, > Dolby surround, Dolby stereo is common. OT: For film on cord Dolby > stereo anyway is nice for stereo, without Dolby there's hardcore wow and > flutter ... hm, regarding to wiki it's called dolby digital, doesn't > matter German filmmakers usually can't pay for Dolby. > > Thanx for the information :) > > Ralf ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On 07/22/10 01:04, Arnold Krille wrote: > And as I said, the more speakers, the better. Not quite. There's an optimal number of speakers for 2d. Optimal in the sense that less speakers result in less resolution and more speakers lead to a blurred image. Flo -- Machines can do the work, so people have time to think. public key DA43FEF4 x-hkp://wwwkeys.eu.pgp.net ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On Fri, 2010-07-23 at 08:51 +0200, Ralf Mardorf wrote: > On Fri, 2010-07-23 at 01:09 +0200, Jörn Nettingsmeier wrote: > > On 07/22/2010 08:42 PM, Ralf Mardorf wrote: > > > > one thing that often gets overlooked: people have learned to accept > > stereo (or, in some circles, 5.1) as the gold standard, and its > > shortcomings have grown into desired features. it's very hard to compete > > with a method that does a few things very well and doesn't even try to > > reproduce most of the auditory cues of, say, a live experience. > > Correct, I like stereo, I don't like 5.1 and indeed stereo is very > limited, but with some training it's good to handle. > If ambisonics shouldn't have the disadvantages of 5.1 I might like it. One crucial difference, please: Ambisonics is a spatialization technique. So called "5.1" is just an arrangement of speakers. It is no more than that. What you don't like is the way the content creators are using that particular arrangement of speakers to render their music (or effects, or whatever). For that they use one or a selection of spatialization techniques of which Ambisonics is just one example - the subject is actually quite complex. I imagine most use just a variation of amplitude panning or something similar. For the same arrangement of speakers (5.1) you could use Ambisonics or any other technique. So, comparing Ambisonics and 5.1 is comparing apples with airplanes (oranges would be too close, they are both fruits). Very different things. -- Fernando ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On Fri, 2010-07-23 at 10:02 -0700, Fernando Lopez-Lezcano wrote: > On Fri, 2010-07-23 at 08:51 +0200, Ralf Mardorf wrote: > > On Fri, 2010-07-23 at 01:09 +0200, Jörn Nettingsmeier wrote: > > > On 07/22/2010 08:42 PM, Ralf Mardorf wrote: > > > > > > one thing that often gets overlooked: people have learned to accept > > > stereo (or, in some circles, 5.1) as the gold standard, and its > > > shortcomings have grown into desired features. it's very hard to compete > > > with a method that does a few things very well and doesn't even try to > > > reproduce most of the auditory cues of, say, a live experience. > > > > Correct, I like stereo, I don't like 5.1 and indeed stereo is very > > limited, but with some training it's good to handle. > > If ambisonics shouldn't have the disadvantages of 5.1 I might like it. > > One crucial difference, please: > > Ambisonics is a spatialization technique. > > So called "5.1" is just an arrangement of speakers. It is no more than > that. What you don't like is the way the content creators are using that > particular arrangement of speakers to render their music (or effects, or > whatever). For that they use one or a selection of spatialization > techniques of which Ambisonics is just one example - the subject is > actually quite complex. I imagine most use just a variation of amplitude > panning or something similar. For the same arrangement of speakers (5.1) > you could use Ambisonics or any other technique. > > So, comparing Ambisonics and 5.1 is comparing apples with airplanes > (oranges would be too close, they are both fruits). Very different > things. > > -- Fernando That gives me hope that I'm wrong about abilities of surround sound :). If I'm mistaken, it will be a win for me :). - Ralf ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On 07/24/2010 10:45 AM, Ralf Mardorf wrote: On Fri, 2010-07-23 at 10:02 -0700, Fernando Lopez-Lezcano wrote: On Fri, 2010-07-23 at 08:51 +0200, Ralf Mardorf wrote: On Fri, 2010-07-23 at 01:09 +0200, Jörn Nettingsmeier wrote: one thing that often gets overlooked: people have learned to accept stereo (or, in some circles, 5.1) as the gold standard, and its shortcomings have grown into desired features. it's very hard to compete with a method that does a few things very well and doesn't even try to reproduce most of the auditory cues of, say, a live experience. Correct, I like stereo, I don't like 5.1 and indeed stereo is very limited, but with some training it's good to handle. If ambisonics shouldn't have the disadvantages of 5.1 I might like it. One crucial difference, please: Ambisonics is a spatialization technique. <...> So, comparing Ambisonics and 5.1 is comparing apples with airplanes (oranges would be too close, they are both fruits). Very different things. That gives me hope that I'm wrong about abilities of surround sound :). If I'm mistaken, it will be a win for me :). i'm soo happy that you benefit from this list. however, it would be very much appreciated if you wasted less of everyone else's INBOX space in the process. at the risk of stating the obvious: think first, then hit "send". your frequent followups to your own mails within a minute and the many non-sequiturs when you hijack other people's threads indicate that this concept might be new to you, which is why i mention it. not that i'm not myself guilty of this once in a while (most everybody is, sometimes), but your posting track record stands out by an order of magnitude. it is also considered socially more acceptable to initiate a learning process by asking carefully phrased questions, not by posting totally ignorant hypotheses that lack even the tiniest bit of factual support, and then caving in when people express their utter bewilderment and going all humble and oh how i want to broaden my horizon... that is funny once, but gets old pretty quick. also, please fix your mailer settings to not cc: people personally, you can assume that everybody is reading the list mails. i for one would really like to see fewer ralf mardorf mails in my inbox, and i have an inkling that many people share this sentiment. that doesn't mean you shouldn't join or start any discussion you like, but please pretty please stop wasting everybody's time and condense your thoughts. no offense, only impact intended, jörn ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On 2010.07.22. 16:45, Arnold Krille wrote: On Thursday 22 July 2010 16:29:01 Chris Cannam wrote: Question that just occurred to me. I'm very ignorant about spatial audio, and although I'm sure several of my colleagues could tell me this, I thought it might be sort of on-topic here. Is it possible, or easy, or sensible, or worthwhile, to reduce a B-format recording into stereo in multiple different ways in order to achieve different subjective "listener position" results when using headphones? It makes sense to reduce B-format to stereo. But the target is important, if you aim at headphones, there are decoders that create an binaural signal. If normal stereo-systems are the target, you will do a decoding similar to any ambisonics setup but only use two speakers in the correct stereo positions and decode to file... The headphone-version gives more of the ambisonics feeling, but the normal stereo signal also benefits from the recording done in ambisonics. I've been studying process of spatialization a bit, and ambisonics figure in there quite a bit. I was wondering if there is some "data loss" if I encode ambisonic format and then decode it to whatever "direct channel-to-speaker" format (stereo, 5.1, others) is needed, in stead of writing to different channels directly. To make it a bit clearer: What difference would these methods cause? 1. Inputs -> B-format -> 5.1 or 2. Inputs -> 5.1 Simply first method allows me to concentrate making ambisonics only, and then use already existing decoders to create final output. ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On Wed, Jul 28, 2010 at 10:47:03PM +0200, JohnLM wrote: > I've been studying process of spatialization a bit, and ambisonics > figure in there quite a bit. > I was wondering if there is some "data loss" if I encode ambisonic > format and then decode it to whatever "direct channel-to-speaker" > format (stereo, 5.1, others) is needed, in stead of writing to > different channels directly. > > To make it a bit clearer: What difference would these methods cause? > 1. Inputs -> B-format -> 5.1 > or > 2. Inputs -> 5.1 > > Simply first method allows me to concentrate making ambisonics only, > and then use already existing decoders to create final output. If you use 2nd order AMB and a good AMB->5.1 decoder the results should be very good. The combimation AMB panner + AMB->5.1 decoder is in fact a 5.1 panner, but quite a sophisticated one. You could put one of theae in each channel, but since the second part is the same for all it's more effficient to do it after the mixing, in other words use an AMB mixing bus. Compared to conventional 5.1 pairwise panning the result will be more even, without emphasising the speaker locations as would be the case otherwise. In other words, the sound will be much less seem to originate in the speakers. Ciao, -- FA There are three of them, and Alleline. ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On Wednesday 28 July 2010 22:47:03 JohnLM wrote: > To make it a bit clearer: What difference would these methods cause? > 1. Inputs -> B-format -> 5.1 > or > 2. Inputs -> 5.1 > Simply first method allows me to concentrate making ambisonics only, and > then use already existing decoders to create final output. Advantages of the first version: If you save the B-format, you can lossless transform the audio to binaural headphone, plain stereo, plain mono, 5.1, 7.1 and all the other zero or first order setups. And you can ship the B-format and have the listeners decode/downmix to what they want/need. Advantages of the second version: Probably none. Apart from the sticker "mixed in 5.1" Have fun, Arnold signature.asc Description: This is a digitally signed message part. ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
f...@kokkinizita.net wrote: On Wed, Jul 28, 2010 at 10:47:03PM +0200, JohnLM wrote: I've been studying process of spatialization a bit, and ambisonics figure in there quite a bit. I was wondering if there is some "data loss" if I encode ambisonic format and then decode it to whatever "direct channel-to-speaker" format (stereo, 5.1, others) is needed, in stead of writing to different channels directly. To make it a bit clearer: What difference would these methods cause? 1. Inputs -> B-format -> 5.1 or 2. Inputs -> 5.1 Simply first method allows me to concentrate making ambisonics only, and then use already existing decoders to create final output. If you use 2nd order AMB and a good AMB->5.1 decoder the results should be very good. That's what I was referring to in my previous email on this subject, although I think we did the decoding "by hand" the result (from a mere subjective point of view was remarkable). What - empirically - struck me is that the 'sweet spot' seemed to be particularly big, that is if I moved off the centre I could still hear things pretty localised, as if you move in along the axis of a stage... Lorenzo The combimation AMB panner + AMB->5.1 decoder is in fact a 5.1 panner, but quite a sophisticated one. You could put one of theae in each channel, but since the second part is the same for all it's more effficient to do it after the mixing, in other words use an AMB mixing bus. Compared to conventional 5.1 pairwise panning the result will be more even, without emphasising the speaker locations as would be the case otherwise. In other words, the sound will be much less seem to originate in the speakers. Ciao, ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On 2010.07.28. 22:06, f...@kokkinizita.net wrote: If you use 2nd order AMB and a good AMB->5.1 decoder the results should be very good. The combimation AMB panner + AMB->5.1 decoder is in fact a 5.1 panner, but quite a sophisticated one. You could put one of theae in each channel, but since the second part is the same for all it's more effficient to do it after the mixing, in other words use an AMB mixing bus. Compared to conventional 5.1 pairwise panning the result will be more even, without emphasising the speaker locations as would be the case otherwise. In other words, the sound will be much less seem to originate in the speakers. I stumbled on your own AMB-Plugins. :) They seem to do pretty much what I need. Mono->B-Format panner provides only angle controls. So from what I can understand, if I apply doppler effect, distance attenuation and other pre-process filters to a mono input and then push it through the panner plugin I get fairly correct representation of sound in 3D space. Right? I failed to find anything discussing mixing in AMB. Can I just sum the channels of all sounds, like I would do it to any "direct-speaker-to-channel" formats? ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
john, On 07/29/2010 02:35 PM, JohnLM wrote: On 2010.07.28. 22:06, f...@kokkinizita.net wrote: Compared to conventional 5.1 pairwise panning the result will be more even, without emphasising the speaker locations as would be the case otherwise. In other words, the sound will be much less seem to originate in the speakers. I stumbled on your own AMB-Plugins. :) They seem to do pretty much what I need. Mono->B-Format panner provides only angle controls. yes. panning is only concerned with angle of incidence, whether in ambisonics, VBAP, or pair-wise stereo. So from what I can understand, if I apply doppler effect, distance attenuation and other pre-process filters to a mono input and then push it through the panner plugin I get fairly correct representation of sound in 3D space. Right? depending on what you mean by "fairly correct", "representation", and "3D space" :-D doppler would come into play only if you change the distance of the sound, not when you move it on the sphere, as the distance remains constant. when you hand-craft distance cues, you should not expect wonders for sounds originating inside your sphere of speakers. travelling through the center quickly can be made to work, though. I failed to find anything discussing mixing in AMB. Can I just sum the channels of all sounds, like I would do it to any "direct-speaker-to-channel" formats? yes. that's a fundamental property of all linear systems, and independent of the signal representation. i've written a little howto for ambi mixing in ardour a while ago, maybe you'll find it useful: http://cec.concordia.ca/econtact/11_3/nettingsmeier_ambisonics.html for lac2010, i tried to find out how ambisonic mixing can be applied to a pop production: http://stackingdwarves.net/public_stuff/linux_audio/lac2010/Field%20Report-A_Pop_production_in_Ambisonics.pdf best, jörn ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On Thursday, July 29, 2010 08:52:04 am Jörn Nettingsmeier did opine: > john, > > On 07/29/2010 02:35 PM, JohnLM wrote: > > On 2010.07.28. 22:06, f...@kokkinizita.net wrote: > >> Compared to conventional 5.1 pairwise panning the result will be > >> more even, without emphasising the speaker locations as would be > >> the case otherwise. In other words, the sound will be much less > >> seem to originate in the speakers. > > > > I stumbled on your own AMB-Plugins. :) > > They seem to do pretty much what I need. Mono->B-Format panner > > provides only angle controls. > > yes. panning is only concerned with angle of incidence, whether in > ambisonics, VBAP, or pair-wise stereo. > > > So from what I can understand, if I apply doppler effect, distance > > attenuation and other pre-process filters to a mono input and then > > push it through the panner plugin I get fairly correct representation > > of sound in 3D space. Right? > > depending on what you mean by "fairly correct", "representation", and > "3D space" :-D > > doppler would come into play only if you change the distance of the > sound, not when you move it on the sphere, as the distance remains > constant. This use of 'doppler' I would call incorrect, because the doppler shift is a shift in the apparent frequency of the sound rising at it approaches, and decreasing as it leaves. I'm sure you have a term for what you mean, but doppler isn't it. That police officers radar gun measures your speed by listening to the echo from your vehicle, and comparing it to the signal its sending, which to simplify, results in a beat frequency which is exactly your speed if approaching or departing exactly to or from the radar guns position. That is why it is often called doppler radar & the weather guys us it also. Because they don't stand directly in front of you to take a reading, there is some small vector error in your favor. Someone else was trying to describe the distance vs square law change in the apparent volumes. So let me try from the broadcast engineering field to explain that better. Imagine a point src of energy, be it light, sound, or other radiation such as a radio or tv signal. Measured at distance x, you will get your reference signal, call it 0 db in this case. Now, without changing anything else move your measuring instrument to a point that is now at a distance of 2x. You don't get half the signal, but 1/4 of it, because the same energy that was hitting a square of any arbitrary measurement, say a square inch, has in addition to being spread twice as wide at distance 2x, it is also twice as high. So the new reading will be -6 db compared to the original '0' db. That is why we call it the square law. The only way to get that back is to make the receptor itself 4 times bigger. But while I have observed that there are quite wide variations in ears, I have not seen an individual with expandable ears (yet) :) > when you hand-craft distance cues, you should not expect wonders for > sounds originating inside your sphere of speakers. travelling through > the center quickly can be made to work, though. > > > I failed to find anything discussing mixing in AMB. Can I just sum the > > channels of all sounds, like I would do it to any > > "direct-speaker-to-channel" formats? > > yes. that's a fundamental property of all linear systems, and > independent of the signal representation. > > i've written a little howto for ambi mixing in ardour a while ago, maybe > you'll find it useful: > http://cec.concordia.ca/econtact/11_3/nettingsmeier_ambisonics.html > for lac2010, i tried to find out how ambisonic mixing can be applied to > a pop production: > http://stackingdwarves.net/public_stuff/linux_audio/lac2010/Field%20Repo > rt-A_Pop_production_in_Ambisonics.pdf > > best, > > jörn > > ___ > Linux-audio-dev mailing list > Linux-audio-dev@lists.linuxaudio.org > http://lists.linuxaudio.org/listinfo/linux-audio-dev -- Cheers, Gene "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) I call them as I see them. If I can't see them, I make them up. -- Biff Barf ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On 2010.07.29. 15:20, Gene Heskett wrote: On Thursday, July 29, 2010 08:52:04 am Jörn Nettingsmeier did opine: john, On 07/29/2010 02:35 PM, JohnLM wrote: So from what I can understand, if I apply doppler effect, distance attenuation and other pre-process filters to a mono input and then push it through the panner plugin I get fairly correct representation of sound in 3D space. Right? depending on what you mean by "fairly correct", "representation", and "3D space" :-D doppler would come into play only if you change the distance of the sound, not when you move it on the sphere, as the distance remains constant. This use of 'doppler' I would call incorrect, because the doppler shift is a shift in the apparent frequency of the sound rising at it approaches, and decreasing as it leaves. I'm sure you have a term for what you mean, but doppler isn't it. That police officers radar gun measures your speed by listening to the echo from your vehicle, and comparing it to the signal its sending, which to simplify, results in a beat frequency which is exactly your speed if approaching or departing exactly to or from the radar guns position. That is why it is often called doppler radar& the weather guys us it also. Because they don't stand directly in front of you to take a reading, there is some small vector error in your favor. Someone else was trying to describe the distance vs square law change in the apparent volumes. So let me try from the broadcast engineering field to explain that better. Imagine a point src of energy, be it light, sound, or other radiation such as a radio or tv signal. Measured at distance x, you will get your reference signal, call it 0 db in this case. Now, without changing anything else move your measuring instrument to a point that is now at a distance of 2x. You don't get half the signal, but 1/4 of it, because the same energy that was hitting a square of any arbitrary measurement, say a square inch, has in addition to being spread twice as wide at distance 2x, it is also twice as high. So the new reading will be -6 db compared to the original '0' db. That is why we call it the square law. The only way to get that back is to make the receptor itself 4 times bigger. But while I have observed that there are quite wide variations in ears, I have not seen an individual with expandable ears (yet) :) when you hand-craft distance cues, you should not expect wonders for sounds originating inside your sphere of speakers. travelling through the center quickly can be made to work, though. I am fairly sure 'doppler' *is* what I meant. I work on spatialization project where sound sources can and will move around on arbitary trajectories in virtual space. Well as for 'distance law'. Microphone receives and registers sound pressure instead of sound intensity. intensity != pressure intensity ~ pressure^2 While true that energy at 2x distance is 1/4, the pressure excerted is 1/2 neverheless (pressure value is independent of area - i.e. it uses constant nominal area). So you end up with a linear correlation instead of square one. pressure ~ 1/distance intensity ~ 1/distance^2 There is also the thing with acoustic impendance. For simplicity I didn't include it into "equations" and that's the reason they're not equalities, but are proportionalities. I failed to find anything discussing mixing in AMB. Can I just sum the channels of all sounds, like I would do it to any "direct-speaker-to-channel" formats? yes. that's a fundamental property of all linear systems, and independent of the signal representation. i've written a little howto for ambi mixing in ardour a while ago, maybe you'll find it useful: http://cec.concordia.ca/econtact/11_3/nettingsmeier_ambisonics.html for lac2010, i tried to find out how ambisonic mixing can be applied to a pop production: http://stackingdwarves.net/public_stuff/linux_audio/lac2010/Field%20Repo rt-A_Pop_production_in_Ambisonics.pdf best, jörn ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On Thu, 2010-07-29 at 17:01 +0200, JohnLM wrote: > On 2010.07.29. 15:20, Gene Heskett wrote: > > On Thursday, July 29, 2010 08:52:04 am Jörn Nettingsmeier did opine: > > > >> john, > >> > >> On 07/29/2010 02:35 PM, JohnLM wrote: > >>> So from what I can understand, if I apply doppler effect, distance > >>> attenuation and other pre-process filters to a mono input and then > >>> push it through the panner plugin I get fairly correct representation > >>> of sound in 3D space. Right? > >> > >> depending on what you mean by "fairly correct", "representation", and > >> "3D space" :-D > >> > >> doppler would come into play only if you change the distance of the > >> sound, not when you move it on the sphere, as the distance remains > >> constant. > > > > This use of 'doppler' I would call incorrect, because the doppler shift is > > a shift in the apparent frequency of the sound rising at it approaches, and > > decreasing as it leaves. I'm sure you have a term for what you mean, but > > doppler isn't it. That police officers radar gun measures your speed by > > listening to the echo from your vehicle, and comparing it to the signal its > > sending, which to simplify, results in a beat frequency which is exactly > > your speed if approaching or departing exactly to or from the radar guns > > position. That is why it is often called doppler radar& the weather guys > > us it also. Because they don't stand directly in front of you to take a > > reading, there is some small vector error in your favor. > > > > Someone else was trying to describe the distance vs square law change in > > the apparent volumes. So let me try from the broadcast engineering field to > > explain that better. Imagine a point src of energy, be it light, sound, > > or other radiation such as a radio or tv signal. Measured at distance x, > > you will get your reference signal, call it 0 db in this case. Now, > > without changing anything else move your measuring instrument to a point > > that is now at a distance of 2x. You don't get half the signal, but 1/4 of > > it, because the same energy that was hitting a square of any arbitrary > > measurement, say a square inch, has in addition to being spread twice as > > wide at distance 2x, it is also twice as high. So the new reading will be > > -6 db compared to the original '0' db. > > > > That is why we call it the square law. The only way to get that back is to > > make the receptor itself 4 times bigger. But while I have observed that > > there are quite wide variations in ears, I have not seen an individual with > > expandable ears (yet) :) > > > >> when you hand-craft distance cues, you should not expect wonders for > >> sounds originating inside your sphere of speakers. travelling through > >> the center quickly can be made to work, though. > > I am fairly sure 'doppler' *is* what I meant. You notice a Doppler effect? So your speakers are far apart from each other, while you are moving very fast from one speaker to the other? Nothing else is called the Doppler effect. There might be a sound similar or equal to a Doppler effect, but of course using this term is bad. > I work on spatialization > project where sound sources can and will move around on arbitary > trajectories in virtual space. > > Well as for 'distance law'. Microphone receives and registers sound > pressure instead of sound intensity. > > intensity != pressure > intensity ~ pressure^2 > > While true that energy at 2x distance is 1/4, the pressure excerted is > 1/2 neverheless (pressure value is independent of area - i.e. it uses > constant nominal area). > So you end up with a linear correlation instead of square one. > > pressure ~ 1/distance > intensity ~ 1/distance^2 > > There is also the thing with acoustic impendance. For simplicity I > didn't include it into "equations" and that's the reason they're not > equalities, but are proportionalities. > > > >>> I failed to find anything discussing mixing in AMB. Can I just sum the > >>> channels of all sounds, like I would do it to any > >>> "direct-speaker-to-channel" formats? > >> > >> yes. that's a fundamental property of all linear systems, and > >> independent of the signal representation. > >> > >> i've written a little howto for ambi mixing in ardour a while ago, maybe > >> you'll find it useful: > >> http://cec.concordia.ca/econtact/11_3/nettingsmeier_ambisonics.html > >> for lac2010, i tried to find out how ambisonic mixing can be applied to > >> a pop production: > >> http://stackingdwarves.net/public_stuff/linux_audio/lac2010/Field%20Repo > >> rt-A_Pop_production_in_Ambisonics.pdf > >> > >> best, > >> > >> jörn > > > ___ > Linux-audio-dev mailing list > Linux-audio-dev@lists.linuxaudio.org > http://lists.linuxaudio.org/listinfo/linux-audio-dev ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/l
Re: [LAD] Attenuation of sounds in 3D space
On Thu, 2010-07-29 at 17:01 +0200, JohnLM wrote: > On 2010.07.29. 15:20, Gene Heskett wrote: > > On Thursday, July 29, 2010 08:52:04 am Jörn Nettingsmeier did opine: > > > >> john, > >> > >> On 07/29/2010 02:35 PM, JohnLM wrote: > >>> So from what I can understand, if I apply doppler effect, distance > >>> attenuation and other pre-process filters to a mono input and then > >>> push it through the panner plugin I get fairly correct representation > >>> of sound in 3D space. Right? > >> > >> depending on what you mean by "fairly correct", "representation", and > >> "3D space" :-D > >> > >> doppler would come into play only if you change the distance of the > >> sound, not when you move it on the sphere, as the distance remains > >> constant. > > > > This use of 'doppler' I would call incorrect, because the doppler shift is > > a shift in the apparent frequency of the sound rising at it approaches, and > > decreasing as it leaves. I'm sure you have a term for what you mean, but > > doppler isn't it. That police officers radar gun measures your speed by > > listening to the echo from your vehicle, and comparing it to the signal its > > sending, which to simplify, results in a beat frequency which is exactly > > your speed if approaching or departing exactly to or from the radar guns > > position. That is why it is often called doppler radar& the weather guys > > us it also. Because they don't stand directly in front of you to take a > > reading, there is some small vector error in your favor. > > > > Someone else was trying to describe the distance vs square law change in > > the apparent volumes. So let me try from the broadcast engineering field to > > explain that better. Imagine a point src of energy, be it light, sound, > > or other radiation such as a radio or tv signal. Measured at distance x, > > you will get your reference signal, call it 0 db in this case. Now, > > without changing anything else move your measuring instrument to a point > > that is now at a distance of 2x. You don't get half the signal, but 1/4 of > > it, because the same energy that was hitting a square of any arbitrary > > measurement, say a square inch, has in addition to being spread twice as > > wide at distance 2x, it is also twice as high. So the new reading will be > > -6 db compared to the original '0' db. > > > > That is why we call it the square law. The only way to get that back is to > > make the receptor itself 4 times bigger. But while I have observed that > > there are quite wide variations in ears, I have not seen an individual with > > expandable ears (yet) :) > > > >> when you hand-craft distance cues, you should not expect wonders for > >> sounds originating inside your sphere of speakers. travelling through > >> the center quickly can be made to work, though. > > I am fairly sure 'doppler' *is* what I meant. I work on spatialization > project where sound sources can and will move around on arbitary > trajectories in virtual space. > > Well as for 'distance law'. Microphone receives and registers sound > pressure instead of sound intensity. > > intensity != pressure > intensity ~ pressure^2 > > While true that energy at 2x distance is 1/4, the pressure excerted is > 1/2 neverheless (pressure value is independent of area - i.e. it uses > constant nominal area). > So you end up with a linear correlation instead of square one. > > pressure ~ 1/distance > intensity ~ 1/distance^2 > > There is also the thing with acoustic impendance. For simplicity I > didn't include it into "equations" and that's the reason they're not > equalities, but are proportionalities. > > > >>> I failed to find anything discussing mixing in AMB. Can I just sum the > >>> channels of all sounds, like I would do it to any > >>> "direct-speaker-to-channel" formats? > >> > >> yes. that's a fundamental property of all linear systems, and > >> independent of the signal representation. > >> > >> i've written a little howto for ambi mixing in ardour a while ago, maybe > >> you'll find it useful: > >> http://cec.concordia.ca/econtact/11_3/nettingsmeier_ambisonics.html > >> for lac2010, i tried to find out how ambisonic mixing can be applied to > >> a pop production: > >> http://stackingdwarves.net/public_stuff/linux_audio/lac2010/Field%20Repo > >> rt-A_Pop_production_in_Ambisonics.pdf > >> > >> best, > >> > >> jörn > > > ___ > Linux-audio-dev mailing list > Linux-audio-dev@lists.linuxaudio.org > http://lists.linuxaudio.org/listinfo/linux-audio-dev When I'm in the cinema I sometimes notice unbearable phasing, while a sound is panned from one 2D position to the other, this isn't a Doppler effect, but an issue regarding to transit time or something else. IMO out of phase vs detune. ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On Thursday, July 29, 2010 11:02:19 am Ralf Mardorf did opine: [...] > When I'm in the cinema I sometimes notice unbearable phasing, while a > sound is panned from one 2D position to the other, this isn't a Doppler > effect, but an issue regarding to transit time or something else. IMO > out of phase vs detune. This I expect, would be an artifact of the usual pan pot, precisely because that pan pot doesn't also put in the phase shifts one normally hears in the real world. For that reason alone, I detest the use of the pan pot on a dynamic basis as an audio editing tool. It simply doesn't do it all, whereas the moving source does. -- Cheers, Gene "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Everything should be built top-down, except the first time. ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On Thu, 2010-07-29 at 11:05 -0400, Gene Heskett wrote: > On Thursday, July 29, 2010 11:02:19 am Ralf Mardorf did opine: > [...] > > When I'm in the cinema I sometimes notice unbearable phasing, while a > > sound is panned from one 2D position to the other, this isn't a Doppler > > effect, but an issue regarding to transit time or something else. IMO > > out of phase vs detune. > > This I expect, would be an artifact of the usual pan pot, precisely because > that pan pot doesn't also put in the phase shifts one normally hears in the > real world. For that reason alone, I detest the use of the pan pot on a > dynamic basis as an audio editing tool. It simply doesn't do it all, > whereas the moving source does. > One of the best mixed recordings I know is THE CRY OF LOVE (J. Hendrix), but unfortunately they did some very annoying pannings (for stereo only). ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On Thu, 2010-07-29 at 16:14 +0200, Ralf Mardorf wrote: > On Thu, 2010-07-29 at 17:01 +0200, JohnLM wrote: > > On 2010.07.29. 15:20, Gene Heskett wrote: > > > On Thursday, July 29, 2010 08:52:04 am Jörn Nettingsmeier did opine: > > > > > >> john, > > >> > > >> On 07/29/2010 02:35 PM, JohnLM wrote: > > >>> So from what I can understand, if I apply doppler effect, distance > > >>> attenuation and other pre-process filters to a mono input and then > > >>> push it through the panner plugin I get fairly correct representation > > >>> of sound in 3D space. Right? > > >> > > >> depending on what you mean by "fairly correct", "representation", and > > >> "3D space" :-D > > >> > > >> doppler would come into play only if you change the distance of the > > >> sound, not when you move it on the sphere, as the distance remains > > >> constant. > > > > > > This use of 'doppler' I would call incorrect, because the doppler shift is > > > a shift in the apparent frequency of the sound rising at it approaches, > > > and > > > decreasing as it leaves. I'm sure you have a term for what you mean, but > > > doppler isn't it. That police officers radar gun measures your speed by > > > listening to the echo from your vehicle, and comparing it to the signal > > > its > > > sending, which to simplify, results in a beat frequency which is exactly > > > your speed if approaching or departing exactly to or from the radar guns > > > position. That is why it is often called doppler radar& the weather guys > > > us it also. Because they don't stand directly in front of you to take a > > > reading, there is some small vector error in your favor. > > > > > >... > > > > > > That is why we call it the square law. The only way to get that back is > > > to > > > make the receptor itself 4 times bigger. But while I have observed that > > > there are quite wide variations in ears, I have not seen an individual > > > with > > > expandable ears (yet) :) > > > > > >> when you hand-craft distance cues, you should not expect wonders for > > >> sounds originating inside your sphere of speakers. travelling through > > >> the center quickly can be made to work, though. > > > > I am fairly sure 'doppler' *is* what I meant. > > You notice a Doppler effect? So your speakers are far apart from each > other, while you are moving very fast from one speaker to the other? > Nothing else is called the Doppler effect. > There might be a sound similar or equal to a Doppler effect, but of > course using this term is bad. You don't understand. The previous posters are talking about _simulating_ moving sound sources. So you, the listener, stay in place, and the composer or sound artist is crafting cues for you that will simulate the movement of sources around you. If those sources move towards or away from you (ie: have a radial component of the velocity vector) then you should simulate the doppler effect they would have if they were real objects. It is a very powerful cue. So, yes, it is doppler and no, use of the term is not bad or incorrect. -- Fernando PS: for example, read: https://ccrma.stanford.edu/courses/220a-fall-2001/chowning.pdf http://www.dxarts.washington.edu/courses/567/08WIN/chowning.pdf ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On Thu, 2010-07-29 at 10:00 -0700, Fernando Lopez-Lezcano wrote: > On Thu, 2010-07-29 at 16:14 +0200, Ralf Mardorf wrote: > > On Thu, 2010-07-29 at 17:01 +0200, JohnLM wrote: > > > On 2010.07.29. 15:20, Gene Heskett wrote: > > > > On Thursday, July 29, 2010 08:52:04 am Jörn Nettingsmeier did opine: > > > > > > > >> john, > > > >> > > > >> On 07/29/2010 02:35 PM, JohnLM wrote: > > > >>> So from what I can understand, if I apply doppler effect, distance > > > >>> attenuation and other pre-process filters to a mono input and then > > > >>> push it through the panner plugin I get fairly correct representation > > > >>> of sound in 3D space. Right? > > > >> > > > >> depending on what you mean by "fairly correct", "representation", and > > > >> "3D space" :-D > > > >> > > > >> doppler would come into play only if you change the distance of the > > > >> sound, not when you move it on the sphere, as the distance remains > > > >> constant. > > > > > > > > This use of 'doppler' I would call incorrect, because the doppler shift > > > > is > > > > a shift in the apparent frequency of the sound rising at it approaches, > > > > and > > > > decreasing as it leaves. I'm sure you have a term for what you mean, > > > > but > > > > doppler isn't it. That police officers radar gun measures your speed by > > > > listening to the echo from your vehicle, and comparing it to the signal > > > > its > > > > sending, which to simplify, results in a beat frequency which is exactly > > > > your speed if approaching or departing exactly to or from the radar guns > > > > position. That is why it is often called doppler radar& the weather > > > > guys > > > > us it also. Because they don't stand directly in front of you to take a > > > > reading, there is some small vector error in your favor. > > > > > > > >... > > > > > > > > That is why we call it the square law. The only way to get that back > > > > is to > > > > make the receptor itself 4 times bigger. But while I have observed that > > > > there are quite wide variations in ears, I have not seen an individual > > > > with > > > > expandable ears (yet) :) > > > > > > > >> when you hand-craft distance cues, you should not expect wonders for > > > >> sounds originating inside your sphere of speakers. travelling through > > > >> the center quickly can be made to work, though. > > > > > > I am fairly sure 'doppler' *is* what I meant. > > > > You notice a Doppler effect? So your speakers are far apart from each > > other, while you are moving very fast from one speaker to the other? > > Nothing else is called the Doppler effect. > > There might be a sound similar or equal to a Doppler effect, but of > > course using this term is bad. > > You don't understand. > > The previous posters are talking about _simulating_ moving sound > sources. So you, the listener, stay in place, and the composer or sound > artist is crafting cues for you that will simulate the movement of > sources around you. If those sources move towards or away from you (ie: > have a radial component of the velocity vector) then you should simulate > the doppler effect they would have if they were real objects. It is a > very powerful cue. > > So, yes, it is doppler and no, use of the term is not bad or incorrect. > > -- Fernando > > PS: for example, read: > https://ccrma.stanford.edu/courses/220a-fall-2001/chowning.pdf > http://www.dxarts.washington.edu/courses/567/08WIN/chowning.pdf At the moment I'll don't read the links, I'll do it another time (ASAP). I guess it was Jörn, who FIRST said "doppler would come into play only if you change the distance of the sound, not when you move it on the sphere, as the distance remains constant." And I do agree. So, for stereo only (or even 'complete' 2D), we do have at least effect of; the 'loudness is the same for all stereo positions' and 'loudness will increase when going near to the centre ', regarding to the mixing console, when using the pan pot. And we also could have some kind of 'out of phase' effect. But a Doppler effect would cause an audible detune effect. As far as I guess to understand it, Doppler is completely out of importance. ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On Thu, 2010-07-29 at 10:00 -0700, Fernando Lopez-Lezcano wrote: > On Thu, 2010-07-29 at 16:14 +0200, Ralf Mardorf wrote: > > On Thu, 2010-07-29 at 17:01 +0200, JohnLM wrote: > > > On 2010.07.29. 15:20, Gene Heskett wrote: > > > > On Thursday, July 29, 2010 08:52:04 am Jörn Nettingsmeier did opine: > > > > > > > >> john, > > > >> > > > >> On 07/29/2010 02:35 PM, JohnLM wrote: > > > >>> So from what I can understand, if I apply doppler effect, distance > > > >>> attenuation and other pre-process filters to a mono input and then > > > >>> push it through the panner plugin I get fairly correct representation > > > >>> of sound in 3D space. Right? > > > >> > > > >> depending on what you mean by "fairly correct", "representation", and > > > >> "3D space" :-D > > > >> > > > >> doppler would come into play only if you change the distance of the > > > >> sound, not when you move it on the sphere, as the distance remains > > > >> constant. > > > > > > > > This use of 'doppler' I would call incorrect, because the doppler shift > > > > is > > > > a shift in the apparent frequency of the sound rising at it approaches, > > > > and > > > > decreasing as it leaves. I'm sure you have a term for what you mean, > > > > but > > > > doppler isn't it. That police officers radar gun measures your speed by > > > > listening to the echo from your vehicle, and comparing it to the signal > > > > its > > > > sending, which to simplify, results in a beat frequency which is exactly > > > > your speed if approaching or departing exactly to or from the radar guns > > > > position. That is why it is often called doppler radar& the weather > > > > guys > > > > us it also. Because they don't stand directly in front of you to take a > > > > reading, there is some small vector error in your favor. > > > > > > > >... > > > > > > > > That is why we call it the square law. The only way to get that back > > > > is to > > > > make the receptor itself 4 times bigger. But while I have observed that > > > > there are quite wide variations in ears, I have not seen an individual > > > > with > > > > expandable ears (yet) :) > > > > > > > >> when you hand-craft distance cues, you should not expect wonders for > > > >> sounds originating inside your sphere of speakers. travelling through > > > >> the center quickly can be made to work, though. > > > > > > I am fairly sure 'doppler' *is* what I meant. > > > > You notice a Doppler effect? So your speakers are far apart from each > > other, while you are moving very fast from one speaker to the other? > > Nothing else is called the Doppler effect. > > There might be a sound similar or equal to a Doppler effect, but of > > course using this term is bad. > > You don't understand. > > The previous posters are talking about _simulating_ moving sound > sources. So you, the listener, stay in place, and the composer or sound > artist is crafting cues for you that will simulate the movement of > sources around you. If those sources move towards or away from you (ie: > have a radial component of the velocity vector) then you should simulate > the doppler effect they would have if they were real objects. It is a > very powerful cue. > > So, yes, it is doppler and no, use of the term is not bad or incorrect. > > -- Fernando > > PS: for example, read: > https://ccrma.stanford.edu/courses/220a-fall-2001/chowning.pdf > http://www.dxarts.washington.edu/courses/567/08WIN/chowning.pdf > > Sorry, you could be right, if you aren't talking about 'realworld' recordings, but about movements by virtual sources. E.g. the 'virtual ambulance' is driving very fast ... not a recording, but a virtual setup. Interesting :). Ralf ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
On Thu, 2010-07-29 at 19:32 +0200, Ralf Mardorf wrote: > On Thu, 2010-07-29 at 10:00 -0700, Fernando Lopez-Lezcano wrote: > > On Thu, 2010-07-29 at 16:14 +0200, Ralf Mardorf wrote: > > > On Thu, 2010-07-29 at 17:01 +0200, JohnLM wrote: > > > > On 2010.07.29. 15:20, Gene Heskett wrote: > > > > > On Thursday, July 29, 2010 08:52:04 am Jörn Nettingsmeier did opine: > > > > > > > > > >> john, > > > > >> > > > > >> On 07/29/2010 02:35 PM, JohnLM wrote: > > > > >>> So from what I can understand, if I apply doppler effect, distance > > > > >>> attenuation and other pre-process filters to a mono input and then > > > > >>> push it through the panner plugin I get fairly correct > > > > >>> representation > > > > >>> of sound in 3D space. Right? > > > > >> > > > > >> depending on what you mean by "fairly correct", "representation", and > > > > >> "3D space" :-D > > > > >> > > > > >> doppler would come into play only if you change the distance of the > > > > >> sound, not when you move it on the sphere, as the distance remains > > > > >> constant. > > > > > > > > > > This use of 'doppler' I would call incorrect, because the doppler > > > > > shift is > > > > > a shift in the apparent frequency of the sound rising at it > > > > > approaches, and > > > > > decreasing as it leaves. I'm sure you have a term for what you mean, > > > > > but > > > > > doppler isn't it. That police officers radar gun measures your speed > > > > > by > > > > > listening to the echo from your vehicle, and comparing it to the > > > > > signal its > > > > > sending, which to simplify, results in a beat frequency which is > > > > > exactly > > > > > your speed if approaching or departing exactly to or from the radar > > > > > guns > > > > > position. That is why it is often called doppler radar& the weather > > > > > guys > > > > > us it also. Because they don't stand directly in front of you to > > > > > take a > > > > > reading, there is some small vector error in your favor. > > > > > > > > > >... > > > > > > > > > > That is why we call it the square law. The only way to get that back > > > > > is to > > > > > make the receptor itself 4 times bigger. But while I have observed > > > > > that > > > > > there are quite wide variations in ears, I have not seen an > > > > > individual with > > > > > expandable ears (yet) :) > > > > > > > > > >> when you hand-craft distance cues, you should not expect wonders for > > > > >> sounds originating inside your sphere of speakers. travelling through > > > > >> the center quickly can be made to work, though. > > > > > > > > I am fairly sure 'doppler' *is* what I meant. > > > > > > You notice a Doppler effect? So your speakers are far apart from each > > > other, while you are moving very fast from one speaker to the other? > > > Nothing else is called the Doppler effect. > > > There might be a sound similar or equal to a Doppler effect, but of > > > course using this term is bad. > > > > You don't understand. > > > > The previous posters are talking about _simulating_ moving sound > > sources. So you, the listener, stay in place, and the composer or sound > > artist is crafting cues for you that will simulate the movement of > > sources around you. If those sources move towards or away from you (ie: > > have a radial component of the velocity vector) then you should simulate > > the doppler effect they would have if they were real objects. It is a > > very powerful cue. > > > > So, yes, it is doppler and no, use of the term is not bad or incorrect. > > > > -- Fernando > > > > PS: for example, read: > > https://ccrma.stanford.edu/courses/220a-fall-2001/chowning.pdf > > http://www.dxarts.washington.edu/courses/567/08WIN/chowning.pdf > > > > > > Sorry, you could be right, if you aren't talking about 'realworld' > recordings, but about movements by virtual sources. > > E.g. the 'virtual ambulance' is driving very fast ... not a recording, > but a virtual setup. > > Interesting :). > > Ralf PS to the German speaking people (perhaps understandable on English too): Imagine that you don't record the "TatüTata" of the police car, but you have got a sampled sound of this noise and you wish to move it by using a pan pot. We would miss the Doppler effect :D. ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] Attenuation of sounds in 3D space
Excerpts from Ralf Mardorf's message of 2010-07-29 19:43:36 +0200: > On Thu, 2010-07-29 at 19:32 +0200, Ralf Mardorf wrote: > > Sorry, you could be right, if you aren't talking about 'realworld' > > recordings, but about movements by virtual sources. > > > > E.g. the 'virtual ambulance' is driving very fast ... not a recording, > > but a virtual setup. > > > > Interesting :). > > > > Ralf > > PS to the German speaking people (perhaps understandable on English > too): > > Imagine that you don't record the "TatüTata" of the police car, but you > have got a sampled sound of this noise and you wish to move it by using > a pan pot. > > We would miss the Doppler effect :D. Reminds me of something that came out of playing with lmms a long time ago. http://download.murks.lima-city.de/kickerV005.mp3 -- Philipp -- "Wir stehen selbst enttäuscht und sehn betroffen / Den Vorhang zu und alle Fragen offen." Bertolt Brecht, Der gute Mensch von Sezuan ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
