Re: [Sursound] Chasing flies with ambisoinics?
Okay, understood. In the course of thinking about this, I've come to the idea that maybe the problem is with the whole concept of spreading like this. When we localise a sound source, there's a lot of information in the transients, which will, of course, have a different spectral signature to the more stead state parts of the sound. The likelihood is therefore that the transients will be panned differently which will, in turn, make for inconsistent imaging, which would explain what I've been hearing with mgspreadpan. Dave On 1 June 2012 17:41, Fons Adriaensen f...@linuxaudio.org wrote: On Thu, May 31, 2012 at 03:26:18PM +0100, Dave Malham wrote: Have you compared the results of having separate X,Y,U,V,P,Q filters to generate the panning (which is how I interpret what you say above) with pre-filtering the sounds then panning the filter outputs? Not sure if I understand the question correctly... But if I do, that is how it works, except that the filtering and panning operations have been collapsed into a single operation. The IRs of all the panned filter outputs are summed, the result is a set of seven filters (the one for W is just a delay, as the others are linear-phase). So for a mono source we get a 1 by 7 convolution matrix, which in this case is the equivalent of 2048 individually panned filter outputs. Ciao, -- FA A world of exhaustive, reliable metadata would be an utopia. It's also a pipe-dream, founded on self-delusion, nerd hubris and hysterically inflated market opportunities. (Cory Doctorow) ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound -- These are my own views and may or may not be shared by my employer Dave Malham Music Research Centre Department of Music The University of York Heslington York YO10 5DD UK Phone 01904 322448 Fax 01904 322450 'Ambisonics - Component Imaging for Audio' ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Chasing flies with ambisoinics?
At 11:49 02/06/2012, Dave Malham wrote: Okay, understood. In the course of thinking about this, I've come to the idea that maybe the problem is with the whole concept of spreading like this. When we localise a sound source, there's a lot of information in the transients, which will, of course, have a different spectral signature to the more stead state parts of the sound. The likelihood is therefore that the transients will be panned differently which will, in turn, make for inconsistent imaging, which would explain what I've been hearing with mgspreadpan. When I listened to the Trinnov demo recording of the Tuba Mirum from Mozart's Requiem, I noticed this effect: the transients (e.g. sibyllants) of the singers were in a different place from the rest of their voices. David ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Chasing flies with ambisoinics?
On Thu, May 31, 2012 at 03:26:18PM +0100, Dave Malham wrote: Have you compared the results of having separate X,Y,U,V,P,Q filters to generate the panning (which is how I interpret what you say above) with pre-filtering the sounds then panning the filter outputs? Not sure if I understand the question correctly... But if I do, that is how it works, except that the filtering and panning operations have been collapsed into a single operation. The IRs of all the panned filter outputs are summed, the result is a set of seven filters (the one for W is just a delay, as the others are linear-phase). So for a mono source we get a 1 by 7 convolution matrix, which in this case is the equivalent of 2048 individually panned filter outputs. Ciao, -- FA A world of exhaustive, reliable metadata would be an utopia. It's also a pipe-dream, founded on self-delusion, nerd hubris and hysterically inflated market opportunities. (Cory Doctorow) ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Chasing flies with ambisoinics?
Hi Fons On 30/05/2012 18:24, Fons Adriaensen wrote: On Wed, May 30, 2012 at 02:10:22PM +0100, Augustine Leudar wrote: but anyone listening carefully would have heard a fly about 1 foot high ! This magnification effect has been reported many times. I wonder how much it has to do with playing back at too high levels. We do associate LF energy and size. Too much of it and the source 'must be' big. That's certainly important - kind of the other end of the scale of quite but distorted sounds can be interpreted as very loud sounds but with a distant source. For sound sources with perceivable angular extensions which are perceived as single objects (pianos, geese and steam loco's have been mentioned in the past), there is an even stronger cue in that for the angles to be right the perceived size of the object is set by the perceived distance which can in turn be modified if the reproduction space reverberation is dominant over the recorded reverberation. Whilst familiarity with the source can overlay some of this , even in York, where we are so familiar with geese ** that there's an informal ban on students recording them, we still find it difficult to hear anything other than Peter Lennox's giant geese when an Ambisonic recording is played back in a reverberant room. Dave ** At present I can see half a dozen Canada geese with young outside my window and some Greylags out on the lake - and I can hear a lot more! . PS - I gather you guys in Parma might be getting pretty shaken up by the earthquakes in Northern Italy - hope all is well there. -- These are my own views and may or may not be shared by my employer /*/ /* Dave Malham http://music.york.ac.uk/staff/research/dave-malham/ */ /* Music Research Centre */ /* Department of Musichttp://music.york.ac.uk/; */ /* The University of York Phone 01904 322448*/ /* Heslington Fax 01904 322450*/ /* York YO10 5DD */ /* UK 'Ambisonics - Component Imaging for Audio' */ /*http://www.york.ac.uk/inst/mustech/3d_audio/; */ /*/ ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Chasing flies with ambisoinics?
Interestingly, he dinosaur size geese (John Leonard's recording when geese go bad) was played in a field, speaker radius 15-20 metres. And the passing motorbike was impressively large, too. AS a rule of thumb, I've always found that one needs to bear in mind the speaker array radius when deciding on the source-mic relationships. Even in a not-very-reverberant outdoor setting, there seems to be some perceptual constancy for speaker distance - this could be using visual, prior knowledge, auditory-only or combination cues. We've observed the same thing for movement plausibility, with recordings of rolling balls. They have to change angle only as much as the rolling sound (which gives reasonable speed cues) would allow, for a particular speaker distance (range). So, if you want to 'scale up' to a bigger rig, then you need to re-pan (where discrete mic recordings are used) - the perceptual understanding of speed draws on far more than change-of-subtended-angle - and when the cues clearly conflict, the mediated nature 'leaps out' at you. Dr Peter Lennox School of Technology University of Derby, UK tel: 01332 593155 e: p.len...@derby.ac.uk -Original Message- From: sursound-boun...@music.vt.edu [mailto:sursound-boun...@music.vt.edu] On Behalf Of Dave Malham Sent: 31 May 2012 09:26 To: Surround Sound discussion group Subject: Re: [Sursound] Chasing flies with ambisoinics? Hi Fons On 30/05/2012 18:24, Fons Adriaensen wrote: On Wed, May 30, 2012 at 02:10:22PM +0100, Augustine Leudar wrote: but anyone listening carefully would have heard a fly about 1 foot high ! This magnification effect has been reported many times. I wonder how much it has to do with playing back at too high levels. We do associate LF energy and size. Too much of it and the source 'must be' big. That's certainly important - kind of the other end of the scale of quite but distorted sounds can be interpreted as very loud sounds but with a distant source. For sound sources with perceivable angular extensions which are perceived as single objects (pianos, geese and steam loco's have been mentioned in the past), there is an even stronger cue in that for the angles to be right the perceived size of the object is set by the perceived distance which can in turn be modified if the reproduction space reverberation is dominant over the recorded reverberation. Whilst familiarity with the source can overlay some of this , even in York, where we are so familiar with geese ** that there's an informal ban on students recording them, we still find it difficult to hear anything other than Peter Lennox's giant geese when an Ambisonic recording is played back in a reverberant room. Dave ** At present I can see half a dozen Canada geese with young outside my window and some Greylags out on the lake - and I can hear a lot more! . PS - I gather you guys in Parma might be getting pretty shaken up by the earthquakes in Northern Italy - hope all is well there. -- These are my own views and may or may not be shared by my employer /*/ /* Dave Malham http://music.york.ac.uk/staff/research/dave-malham/ */ /* Music Research Centre */ /* Department of Musichttp://music.york.ac.uk/; */ /* The University of York Phone 01904 322448*/ /* Heslington Fax 01904 322450*/ /* York YO10 5DD */ /* UK 'Ambisonics - Component Imaging for Audio' */ /*http://www.york.ac.uk/inst/mustech/3d_audio/; */ /*/ ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound _ The University of Derby has a published policy regarding email and reserves the right to monitor email traffic. If you believe this email was sent to you in error, please notify the sender and delete this email. Please direct any concerns to info...@derby.ac.uk. ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Chasing flies with ambisoinics?
Hi Dave, This magnification effect has been reported many times. I wonder how much it has to do with playing back at too high levels. We do associate LF energy and size. Too much of it and the source 'must be' big. That's certainly important - kind of the other end of the scale of quite but distorted sounds can be interpreted as very loud sounds but with a distant source. For sound sources with perceivable angular extensions which are perceived as single objects (pianos, geese and steam loco's have been mentioned in the past), there is an even stronger cue in that for the angles to be right the perceived size of the object is set by the perceived distance which can in turn be modified if the reproduction space reverberation is dominant over the recorded reverberation. That is certainly the case for the new 3rd order AMB (horizontal only) system installed recently in la Casa del Suono (which is a small church, so quite reverberant). It works great for concerts, which is what is was designed to do, but for most recorded material indeed any sense of distance is lost. I did a small experiment a few weeks ago, and was quite surprised by the result. In a concert we did at the CdS there were three pieces for solo flute and 'tape'. We got the 'tapes' as CDs of course. The artistic director of the festival asked me if I could somehow 'spatialize' the tapes instead of just playing them via two speakers. There wasn't much time to do anything fancy, so I created six filters, one for each of X,Y,U,V,P,Q which would distribute a mono source in function of frequency, with one full cycle in azimuth for each octave. In fact I made two sets, one going clockwise and the second in the opposite sense. The tapes were all electronic noises, nothing you could recognise as a natural sound, and it worked quite well. Afterwards I took the filter set to the studio at the CdM which also has 3rd order monitoring, and used it on some non-electronic music recordings. Of course this produces quite unnatural effects, sounds which you know as from a single source are split in direction (but 2nd and 4th harmonic would coincide with the fundamental). Each of the speaker signals separately is extremely coloured, and when you solo them in the right order you get the 'infinitely ascending pitch' effect. What surprised me is that nobody could associate pitch and speakers. I somehow expected it would be obvious that e.g. all 'C' notes would come from the same direction, and that one would be able to identify the pitch of each speaker when listening to the complete signal. But that was not the case, and you had to go quite close to any speaker in order to notice there was something strange with the sound it produced. PS - I gather you guys in Parma might be getting pretty shaken up by the earthquakes in Northern Italy - hope all is well there. Here in Parma there's no major damage so far, but in the region just NE of Modena (60..70 km from here) it's dire misery. 16 people died on monday, mostly employees who were just resuming work a week after the first shock. And very probably it's not finished, there are lots of small tremors all day and night, and some more big ones can be expected. Ciao, -- FA A world of exhaustive, reliable metadata would be an utopia. It's also a pipe-dream, founded on self-delusion, nerd hubris and hysterically inflated market opportunities. (Cory Doctorow) ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Chasing flies with ambisoinics?
Hi Fons On 31/05/2012 14:42, Fons Adriaensen wrote: I did a small experiment a few weeks ago, and was quite surprised by the result. In a concert we did at the CdS there were three pieces for solo flute and 'tape'. We got the 'tapes' as CDs of course. The artistic director of the festival asked me if I could somehow 'spatialize' the tapes instead of just playing them via two speakers. There wasn't much time to do anything fancy, so I created six filters, one for each of X,Y,U,V,P,Q which would distribute a mono source in function of frequency, with one full cycle in azimuth for each octave. In fact I made two sets, one going clockwise and the second in the opposite sense. The tapes were all electronic noises, nothing you could recognise as a natural sound, and it worked quite well. Afterwards I took the filter set to the studio at the CdM which also has 3rd order monitoring, and used it on some non-electronic music recordings. Of course this produces quite unnatural effects, sounds which you know as from a single source are split in direction (but 2nd and 4th harmonic would coincide with the fundamental). Each of the speaker signals separately is extremely coloured, and when you solo them in the right order you get the 'infinitely ascending pitch' effect. What surprised me is that nobody could associate pitch and speakers. I somehow expected it would be obvious that e.g. all 'C' notes would come from the same direction, and that one would be able to identify the pitch of each speaker when listening to the complete signal. But that was not the case, and you had to go quite close to any speaker in order to notice there was something strange with the sound it produced. That's interesting - it kind of chimes with some experiments I have been doing recently with digital recreations of Gerzon's spreaders, which used phase shift based processing. Although technically they are doing what is described in MAG's original hand written reports, the way they sound doesn't really correspond very closely to description of how they should sound in the same report. Whilst a broadband sound processed through one of my pluggins (imaginatively named 'mgspreadpan') does lose the sense of being a point source as you turn the spread up, there's no clear feeling that sounds of particular frequencies are coming from a particular direction. Have you compared the results of having separate X,Y,U,V,P,Q filters to generate the panning (which is how I interpret what you say above) with pre-filtering the sounds then panning the filter outputs? PS - I gather you guys in Parma might be getting pretty shaken up by the earthquakes in Northern Italy - hope all is well there. Here in Parma there's no major damage so far, but in the region just NE of Modena (60..70 km from here) it's dire misery. 16 people died on monday, mostly employees who were just resuming work a week after the first shock. And very probably it's not finished, there are lots of small tremors all day and night, and some more big ones can be expected. Glad to hear that you are ok and hope that it stays that way, All the best Dave -- These are my own views and may or may not be shared by my employer /*/ /* Dave Malham http://music.york.ac.uk/staff/research/dave-malham/ */ /* Music Research Centre */ /* Department of Musichttp://music.york.ac.uk/; */ /* The University of York Phone 01904 322448*/ /* Heslington Fax 01904 322450*/ /* York YO10 5DD */ /* UK 'Ambisonics - Component Imaging for Audio' */ /*http://www.york.ac.uk/inst/mustech/3d_audio/; */ /*/ ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Chasing flies with ambisoinics?
Thats pretty similar to an example I heard the other day. A composer had split the sound of a cello into different frequency bands and dispersed them around a lot of loudspeakers (in a line if I remember correctly) each one playing a different frequency - imagine his dissapointment when the human auditroy system summed all the frequencies back up again and and allocated the sound source and its entire set of frequency bands to one blurry spot. The solution it turned out to be that he had to decorrolate and desynchronise (slightly) the signals and frequancy bands to each speaker and then , and only then, did he achieve the spatialisation effect he looked for. Gary Kendal explains it very well in his paper why things don't work section 3.8. Why do I still hear single image when I put the harmonics of a sound in different loudspeakers? What surprised me is that nobody could associate pitch and speakers. I somehow expected it would be obvious that e.g. all 'C' notes would come from the same direction, and that one would be able to identify the pitch of each speaker when listening to the complete signal. But that was not the case, and you had to go quite close to any speaker in order to notice there was something strange with the sound it produced. -- next part -- An HTML attachment was scrubbed... URL: https://mail.music.vt.edu/mailman/private/sursound/attachments/20120531/82abef66/attachment.html ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Chasing flies with ambisoinics? (was Re: microphone epiphany ?)
On 05/29/2012 08:24 PM, Bearcat M. Şandor wrote: This touches on something i've wondered for a while now. Discrete surround always sounds as though it's in a fixed ring to me. Sounds are always the same distance away. I've experianced that with binaural recordings as well. Is there a surround sound method that will reproduce actual depth enough so that you could track the movment of a fly in a room? I'd love a system where i could hear a fly moving towards my face, veering off a few inches away, moving at a diagonal to 5' away then zig-zaging back and around my head. Would the lack of a visual component effect that strongly? I can still locate a fly without seeing it. Can ambisonics do that with a good mic for the W? doing it correctly requires very high orders, or a very dense wfs system. all first order ambisonics could do is take a lucky shot at psychoacoustics, and then it may work well for a few people, but certainly not for the majority of listeners. -- Jörn Nettingsmeier Lortzingstr. 11, 45128 Essen, Tel. +49 177 7937487 Meister für Veranstaltungstechnik (Bühne/Studio) Tonmeister VDT http://stackingdwarves.net ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Chasing flies with ambisoinics?
This is also something I've been wondering about and trying to achieve in sound installations. A fly landed on a microphone once when I was recording in the jungle and when played back it sort of worked - sort of - but I do think the cognitive visual factors (the sound installation was in a large indoor jungle at the eden project) helped enormously with believability - but anyone listening carefully would have heard a fly about 1 foot high ! I am told Wavefiled synthesis what you decribe , though haven't heard it myelf - I will be building a small WFS setup this summer - quite looking forward to hearing it. Another low tech solution which is really crude but would probably work would be to have a tiny speaker on an invisible string and pulley system pulling it round the room. We are considering introducing fireflies to the sound installation this year and that was one idea that crossed my mind Realistic proximity is a tricky thing to achieve ! FA This touches on something i've wondered for a while now. Discrete surround always sounds as though it's in a fixed ring to me. Sounds are always the same distance away. I've experianced that with binaural recordings as well. Is there a surround sound method that will reproduce actual depth enough so that you could track the movment of a fly in a room? I'd love a system where i could hear a fly moving towards my face, veering off a few inches away, moving at a diagonal to 5' away then zig-zaging back and around my head. Would the lack of a visual component effect that strongly? I can still locate a fly without seeing it. Can ambisonics do that with a good mic for the W? Thanks, Bearcat -- next part -- A non-text attachment was scrubbed... Name: not available Type: application/pgp-signature Size: 198 bytes Desc: not available URL: https://mail.music.vt.edu/mailman/private/sursound/attachments/20120529/b153f60d/attachment.bin ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound -- next part -- An HTML attachment was scrubbed... URL: https://mail.music.vt.edu/mailman/private/sursound/attachments/20120530/352e76fd/attachment.html ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Chasing flies with ambisoinics?
One thing to bear in mind is that the perception of proximity is far easier to achieve with (fairly rapidly) moving sources. If you get the changing patterns of simulated early reflections right, the ear/brain will focus on the consistent cues (early reflections) and tend to ignore the inconsistent ones like the direct to reverb ratio. Unfortunately, once the sound stops moving, the direct to reverb ratio becomes more consistent, so However, with any loudspeaker based system, you are continually battling against the loudspeaker radius (a.k.a. reverberation radius or critical distance) problem - that is, the sound from a loudspeaker (or loudspeakers) always tries to sound like it is coming from not less than the distance of the loudspeaker, simply because (one of) the strongest distance cue is the ratio of direct to reverberant sound. It's easier if you have a very dead room and the soundscape you are trying to reproduce has noticeably more reverberation, since you can then get the direct-to-reverberant ratio more closely right. Not that it's easier with WFS or HOA to get some of the other cues right, such as wavefront curvature and this helps greatly - but is not a panacea. There are only two ways (at present) that I am aware of in which you can, even theoretically, do it - short of physically having moving loudspeakers. The first is individually headtracked binaural synthesis over headphones, the other is the use of steerable spots of sound produced by crossing, modulated ultrasonic beams - a bit like Holophonics http://www.holosonics.com/ Acoustic Spotlights but with more widely spread transducers, so that the demodulation only occurs where the beams cross. Dave On 30/05/2012 14:10, Augustine Leudar wrote: This is also something I've been wondering about and trying to achieve in sound installations. A fly landed on a microphone once when I was recording in the jungle and when played back it sort of worked - sort of - but I do think the cognitive visual factors (the sound installation was in a large indoor jungle at the eden project) helped enormously with believability - but anyone listening carefully would have heard a fly about 1 foot high ! I am told Wavefiled synthesis what you decribe , though haven't heard it myelf - I will be building a small WFS setup this summer - quite looking forward to hearing it. Another low tech solution which is really crude but would probably work would be to have a tiny speaker on an invisible string and pulley system pulling it round the room. We are considering introducing fireflies to the sound installation this year and that was one idea that crossed my mind Realistic proximity is a tricky thing to achieve ! FA This touches on something i've wondered for a while now. Discrete surround always sounds as though it's in a fixed ring to me. Sounds are always the same distance away. I've experianced that with binaural recordings as well. Is there a surround sound method that will reproduce actual depth enough so that you could track the movment of a fly in a room? I'd love a system where i could hear a fly moving towards my face, veering off a few inches away, moving at a diagonal to 5' away then zig-zaging back and around my head. Would the lack of a visual component effect that strongly? I can still locate a fly without seeing it. Can ambisonics do that with a good mic for the W? Thanks, Bearcat -- next part -- A non-text attachment was scrubbed... Name: not available Type: application/pgp-signature Size: 198 bytes Desc: not available URL: https://mail.music.vt.edu/mailman/private/sursound/attachments/20120529/b153f60d/attachment.bin ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound -- next part -- An HTML attachment was scrubbed... URL:https://mail.music.vt.edu/mailman/private/sursound/attachments/20120530/352e76fd/attachment.html ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound -- These are my own views and may or may not be shared by my employer /*/ /* Dave Malham http://music.york.ac.uk/staff/research/dave-malham/ */ /* Music Research Centre */ /* Department of Musichttp://music.york.ac.uk/; */ /* The University of York Phone 01904 322448*/ /* Heslington Fax 01904 322450*/ /* York YO10 5DD */ /* UK 'Ambisonics - Component Imaging for Audio' */ /*http://www.york.ac.uk/inst/mustech/3d_audio/; */ /*/ -- next part
Re: [Sursound] Chasing flies with ambisoinics?
Wow - thats real startrek material right there Dave ! I was letting my imagination wander in a similar area the other day and was wondering if the beating/harmonics caused by two beams of electromagnetic waves could somehow excite the air where their paths crossed causing a sound to eminate from that spot. Although it may sound a bit out there I found out from a PHD student that there some Russians doing something vaguely similar already except they are doing it the other way round - using ultrasound propogated in a liquid to create light : http://www.myspace.com/video/12k-line/evelina-domnitch-dmitry-gelfand-quot-xenon-wind-quot-camera-lucida-dvd/7806818 On 30/05/2012, Dave Malham dave.mal...@york.ac.uk wrote: One thing to bear in mind is that the perception of proximity is far easier to achieve with (fairly rapidly) moving sources. If you get the changing patterns of simulated early reflections right, the ear/brain will focus on the consistent cues (early reflections) and tend to ignore the inconsistent ones like the direct to reverb ratio. Unfortunately, once the sound stops moving, the direct to reverb ratio becomes more consistent, so However, with any loudspeaker based system, you are continually battling against the loudspeaker radius (a.k.a. reverberation radius or critical distance) problem - that is, the sound from a loudspeaker (or loudspeakers) always tries to sound like it is coming from not less than the distance of the loudspeaker, simply because (one of) the strongest distance cue is the ratio of direct to reverberant sound. It's easier if you have a very dead room and the soundscape you are trying to reproduce has noticeably more reverberation, since you can then get the direct-to-reverberant ratio more closely right. Not that it's easier with WFS or HOA to get some of the other cues right, such as wavefront curvature and this helps greatly - but is not a panacea. There are only two ways (at present) that I am aware of in which you can, even theoretically, do it - short of physically having moving loudspeakers. The first is individually headtracked binaural synthesis over headphones, the other is the use of steerable spots of sound produced by crossing, modulated ultrasonic beams - a bit like Holophonics http://www.holosonics.com/ Acoustic Spotlights but with more widely spread transducers, so that the demodulation only occurs where the beams cross. Dave ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Chasing flies with ambisoinics?
Of course, the other way is to attach a small, high power speaker to a trained fly Dr Peter Lennox School of Technology University of Derby, UK tel: 01332 593155 e: p.len...@derby.ac.uk -Original Message- From: sursound-boun...@music.vt.edu [mailto:sursound-boun...@music.vt.edu] On Behalf Of Augustine Leudar Sent: 30 May 2012 15:18 To: Surround Sound discussion group Subject: Re: [Sursound] Chasing flies with ambisoinics? Wow - thats real startrek material right there Dave ! I was letting my imagination wander in a similar area the other day and was wondering if the beating/harmonics caused by two beams of electromagnetic waves could somehow excite the air where their paths crossed causing a sound to eminate from that spot. Although it may sound a bit out there I found out from a PHD student that there some Russians doing something vaguely similar already except they are doing it the other way round - using ultrasound propogated in a liquid to create light : http://www.myspace.com/video/12k-line/evelina-domnitch-dmitry-gelfand-quot-xenon-wind-quot-camera-lucida-dvd/7806818 On 30/05/2012, Dave Malham dave.mal...@york.ac.uk wrote: One thing to bear in mind is that the perception of proximity is far easier to achieve with (fairly rapidly) moving sources. If you get the changing patterns of simulated early reflections right, the ear/brain will focus on the consistent cues (early reflections) and tend to ignore the inconsistent ones like the direct to reverb ratio. Unfortunately, once the sound stops moving, the direct to reverb ratio becomes more consistent, so However, with any loudspeaker based system, you are continually battling against the loudspeaker radius (a.k.a. reverberation radius or critical distance) problem - that is, the sound from a loudspeaker (or loudspeakers) always tries to sound like it is coming from not less than the distance of the loudspeaker, simply because (one of) the strongest distance cue is the ratio of direct to reverberant sound. It's easier if you have a very dead room and the soundscape you are trying to reproduce has noticeably more reverberation, since you can then get the direct-to-reverberant ratio more closely right. Not that it's easier with WFS or HOA to get some of the other cues right, such as wavefront curvature and this helps greatly - but is not a panacea. There are only two ways (at present) that I am aware of in which you can, even theoretically, do it - short of physically having moving loudspeakers. The first is individually headtracked binaural synthesis over headphones, the other is the use of steerable spots of sound produced by crossing, modulated ultrasonic beams - a bit like Holophonics http://www.holosonics.com/ Acoustic Spotlights but with more widely spread transducers, so that the demodulation only occurs where the beams cross. Dave ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound _ The University of Derby has a published policy regarding email and reserves the right to monitor email traffic. If you believe this email was sent to you in error, please notify the sender and delete this email. Please direct any concerns to info...@derby.ac.uk. ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Chasing flies with ambisoinics?
In the early seventies, I remember Trevor Wishart doing a spatial audio piece by putting battery powered cassette recorders in suitcases and having the performers move around carrying them (and I'm sure there have been other such...) However, back to the present - given the progress the military are making on miniaturising spy drones, these would probably be a better bet than the average fly :-) Dave On 30/05/2012 15:19, Peter Lennox wrote: Of course, the other way is to attach a small, high power speaker to a trained fly Dr Peter Lennox School of Technology University of Derby, UK tel: 01332 593155 e: p.len...@derby.ac.uk -Original Message- From: sursound-boun...@music.vt.edu [mailto:sursound-boun...@music.vt.edu] On Behalf Of Augustine Leudar Sent: 30 May 2012 15:18 To: Surround Sound discussion group Subject: Re: [Sursound] Chasing flies with ambisoinics? Wow - thats real startrek material right there Dave ! I was letting my imagination wander in a similar area the other day and was wondering if the beating/harmonics caused by two beams of electromagnetic waves could somehow excite the air where their paths crossed causing a sound to eminate from that spot. Although it may sound a bit out there I found out from a PHD student that there some Russians doing something vaguely similar already except they are doing it the other way round - using ultrasound propogated in a liquid to create light : http://www.myspace.com/video/12k-line/evelina-domnitch-dmitry-gelfand-quot-xenon-wind-quot-camera-lucida-dvd/7806818 On 30/05/2012, Dave Malhamdave.mal...@york.ac.uk wrote: One thing to bear in mind is that the perception of proximity is far easier to achieve with (fairly rapidly) moving sources. If you get the changing patterns of simulated early reflections right, the ear/brain will focus on the consistent cues (early reflections) and tend to ignore the inconsistent ones like the direct to reverb ratio. Unfortunately, once the sound stops moving, the direct to reverb ratio becomes more consistent, so However, with any loudspeaker based system, you are continually battling against the loudspeaker radius (a.k.a. reverberation radius or critical distance) problem - that is, the sound from a loudspeaker (or loudspeakers) always tries to sound like it is coming from not less than the distance of the loudspeaker, simply because (one of) the strongest distance cue is the ratio of direct to reverberant sound. It's easier if you have a very dead room and the soundscape you are trying to reproduce has noticeably more reverberation, since you can then get the direct-to-reverberant ratio more closely right. Not that it's easier with WFS or HOA to get some of the other cues right, such as wavefront curvature and this helps greatly - but is not a panacea. There are only two ways (at present) that I am aware of in which you can, even theoretically, do it - short of physically having moving loudspeakers. The first is individually headtracked binaural synthesis over headphones, the other is the use of steerable spots of sound produced by crossing, modulated ultrasonic beams - a bit like Holophonics http://www.holosonics.com/ Acoustic Spotlights but with more widely spread transducers, so that the demodulation only occurs where the beams cross. Dave ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound _ The University of Derby has a published policy regarding email and reserves the right to monitor email traffic. If you believe this email was sent to you in error, please notify the sender and delete this email. Please direct any concerns to info...@derby.ac.uk. ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound -- These are my own views and may or may not be shared by my employer /*/ /* Dave Malham http://music.york.ac.uk/staff/research/dave-malham/ */ /* Music Research Centre */ /* Department of Musichttp://music.york.ac.uk/; */ /* The University of York Phone 01904 322448*/ /* Heslington Fax 01904 322450*/ /* York YO10 5DD */ /* UK 'Ambisonics - Component Imaging for Audio' */ /*http://www.york.ac.uk/inst/mustech/3d_audio/; */ /*/ ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Chasing flies with ambisoinics?
On Wed, May 30, 2012 at 02:10:22PM +0100, Augustine Leudar wrote: but anyone listening carefully would have heard a fly about 1 foot high ! This magnification effect has been reported many times. I wonder how much it has to do with playing back at too high levels. We do associate LF energy and size. Too much of it and the source 'must be' big. Ciao, -- FA A world of exhaustive, reliable metadata would be an utopia. It's also a pipe-dream, founded on self-delusion, nerd hubris and hysterically inflated market opportunities. (Cory Doctorow) ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Chasing flies with ambisoinics?
Kind of already happening ! Not exactly a virtuoso performance but still pretty cool : Miniature flying robots play James Bond theme : http://www.youtube.com/watch?v=_sUeGC-8dyk No if we could just get the noise levels of the robots down and fix a small speaker on their backs I think interesting things could occur On 30 May 2012 15:47, Dave Malham dave.mal...@york.ac.uk wrote: In the early seventies, I remember Trevor Wishart doing a spatial audio piece by putting battery powered cassette recorders in suitcases and having the performers move around carrying them (and I'm sure there have been other such...) However, back to the present - given the progress the military are making on miniaturising spy drones, these would probably be a better bet than the average fly :-) Dave tic Spotlights -- next part -- An HTML attachment was scrubbed... URL: https://mail.music.vt.edu/mailman/private/sursound/attachments/20120530/d98fd64a/attachment.html ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Chasing flies with ambisoinics?
Is there a surround sound method that will reproduce actual depth enough so that you could track the movment of a fly in a room? A while back I started making a series of simultaneous binaural and 1st-order soundfield recordings. The purpose is to compare them in reproduction, with a couple of goals in mind. I'll leave those goals aside for the moment. The rig is comprised of a dummy head constructed according to ITU-T P.58 and either a DPA-4 (for fixed recording situations) tetrahedral microphone or a Tetramic (for mobile recordings). A necessary intermediate step has been to perform a diffuse-field calibration of both the soundfield microphones and the dummy head. That has now been done. I made need to do it again, but at the moment I have something that seems satisfactory. One of those recordings was of a fly buzzing around the manikin. As soon as Ambisonia is up and running again I'll post some of those recordings. Eric Benjamin ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Chasing flies with ambisoinics?
The problem is, a sound sources as close to your ear as a mosquito is essentially a mono signal on one ear, you practically hear nothing on the other ear. That's pretty much impossible to do with anything than a headphone setup, or some phase cancelation while your head is clamped down such as not to move. So the realism gets lost on things that sound loud without being loud, because they are so damn close to an ear. I wonder if there's a formal specification as to the distance and volume of objects that can be reasonably accurately modeled with a speaker array given the constraints of the human head size. Ronald On 30 May 2012, at 14:29, Augustine Leudar augustineleu...@gmail.com wrote: Thats probably it - but if it had been quieter it wouldnt have been heard at all or rather it would have sounded like a distant bee . The thing is when an insect flies really close to your ear its a really loud almost a physical sensation .I was trying to get that effect when I fly or mosquito flies really close to your ear and you brush it away. I would be difficult to get those sort of pressure levels any quieter from a loudspeaker on the other side of the path - Under the circumstances I was prepared to accept a one foot fly but to be realistic its not going to sound anything like real life without WFS or something similar (Im all for the training a fly solution myself) . On 30 May 2012 18:24, Fons Adriaensen f...@linuxaudio.org wrote: On Wed, May 30, 2012 at 02:10:22PM +0100, Augustine Leudar wrote: but anyone listening carefully would have heard a fly about 1 foot high ! This magnification effect has been reported many times. I wonder how much it has to do with playing back at too high levels. We do associate LF energy and size. Too much of it and the source 'must be' big. ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
