Re: [Sursound] Sound Externalization Headphone
Dear List, Could anyone share the sound externalized data for headphone rendering with me? Thank you so much. Best regards, Junfeng On Wed, Jun 1, 2011 at 4:54 PM, Junfeng Li junfeng.li.1...@gmail.comwrote: Dear Filippo, all friends, According to your comments, we have processed the binaural sound by performing headphone equalization and adding reverberation. The processed data can be downloaded from https://proself2.jaist.ac.jp/public/pVFAAA0MP8dAqTcB6R4w7AJKMfhlt8TlYUr-IojOpP-Z (test_src: the original sound; test_synthesis: the processed sound) Could you listen to them and give me your own ideas on the synthesized data? Of course, the headphone that you will use is different from mine, while its effect should be not so significant, i think. We are now studying head-tracking which is expected to be added in the near future. And the individualization of HRTFs is quite difficult in real situation, therefore, I cannot do it currently. Thank you so much for your comments on our data and our research. Best regards, Junfeng On Thu, May 26, 2011 at 10:09 PM, f...@libero.it f...@libero.it wrote: Dear Junfeng decorrelation is a term quite loosely used in the audio community, I believe. You can find a definition of correlation in any good signal processing book. It is the convolution of a signal with the time reversed version of another signal. If this function is a delta, then the two signals are perfectly correlated, if it is similar to noise, they are uncorelated. You can think about white noise: if you generate a burst of white noise and you correlate with itself, you'll get more or less a delta function. If you plat these two identical throug a stereo system, you will preceive a virtual acoustic image between the speakers. If you now correlate the previous noise with a different burst of white noise, you'll get noise again (namely, the two signals are not correlated). If you play these two diffrent signals through the same stereo system, I believe you will perceive two separate noise sources. If you think about a binaural signal obtained by convolving a mono signal with an HRTF for 0 elevation and 0 azimuth, the left and right signals are going to be the same (assuming symmetry of the head/torso). Decorrelating the two signals mainly means to add some randomization of the phase of teh two signals, so that they are not exactly the same. In practice, this correspods to convolving the signals with two diffrent all-pass filters. Usually, these filters are chosen to be short bursts of white noise with and exponential decay. You might argue that this is more or less the same as adding some reverberation, and I would indeed agree with you... in fact a binaural reverberation (with IACC smaller than 1) decorrelates the right and left signal and gives apparently an idea of spaciousness and helps greately with the externalization. I think some suggestions on how to decorrelate signals can be found in Laitinen' s thesis. I hope this helps... Filippo Messaggio originale Da: junfeng.li.1...@gmail.com Data: 26/05/2011 15.28 A: f...@libero.itf...@libero.it, Surround Sound discussion group sursound@music.vt.edu Ogg: Re: [Sursound] Sound Externalization Headphone Dear Filippo, Thanks a lot for your quite valuable comments. Apparently, as Akis and Joern mentioned, the following items often are used to achieve externalization: - decorrelation/reverberation - head tracking - individualized HRTF - headphone equalization What I am now confusing is what you mean by decorrelation/reverberation? How to do decorrelation? for What? Thank you so much in advance. Cheers, Junfeng We believe that the order of the items above reflects their relevance (in decreasing order). At the London AES, I discussed this with some researchers from Aalto Uni (they gave me an extremely impressive demo when I visited their lab in Helsinki). They stressed the fact that a visual reference to the virtual sound source location is an extremely important localization cue... I should mention that interpolation of HRTF is not the only possible technique; you can use for example a virtual loudspeaker array... Does the Dolby product implement head tracking? Hope this helps Filippo From: Archontis Politis deadflagb...@gmail.com Subject: Re: [Sursound] Sound Externalization Headphone To: sursound@music.vt.edu Message-ID: 4ddbca43.20...@gmail.com Content-Type: text/plain; charset=ISO-8859-1; format=flowed Hi, I would add to J?rn's comments that apart from head-tracking, which is crucial, you probably have to apply some decorrelation to your synthetic binaural signals, and mix them with the normal ones. From anechoic hrtfs only, especially if they are generic ones it is easy to get the in-head effect. You can add decorrelation by some room simulation algorithm, artificial reverberation or simpler
Re: [Sursound] Sound Externalization Headphone
Hi You seem to have made a very advanced head tracking device, Did you ever consider to use wii for head tracking? http://rpavlik.github.com/wiimote-head-tracker-gui/ Wii headtracking in VR Juggler through VRPN http://www.xs4all.nl/~wognum/wii/ http://www.wiimoteproject.com/ Regards Bo-Erik -Original Message- From: sursound-boun...@music.vt.edu [mailto:sursound-boun...@music.vt.edu] On Behalf Of Hector Centeno Sent: den 25 maj 2011 23:15 To: Surround Sound discussion group Subject: Re: [Sursound] Sound Externalization Headphone Exactly what I've been exploring using ambisonic recordings from a tetrahedral mic. I've been decoding to fixed HRTFs corresponding to virtual speakers in a cube configuration. Good to know who was doing it and when was already being done. I also made a head-tracking sensor using an accelerometer, gyroscope and magnetometer controlled by an Arduino Pro Mini: http://vimeo.com/22727528 Cheers, Hector On Wed, May 25, 2011 at 4:06 AM, Dave Malham dave.mal...@york.ac.uk wrote: On 24/05/2011 20:00, f...@libero.it wrote: snip I should mention that interpolation of HRTF is not the only possible technique; you can use for example a virtual loudspeaker array... This is certainly the way that the Lake DSP system worked that they demonstrated way back in 1993 (I think it's in the papers for the London VR93 confence from that year but I don't have my copy of the proceedings hand). The sounds were recorded in (first order) Ambisonics and the head tracking drove a rotate/tilt algorithme that fed a decoder to virtual speakers the signals from which were convolved with fixed hrtf's corresponding to the speakers' positions that were fixed wrt the head, mixed together and fed to the headphones. Dave ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Sound Externalization Headphone
so what happens is you take the positions of the speakers you want to simulate, and convolve each speaker signal with the appropriate head-related transfer functions for the left and right ear. Can I bring a concern here? I have compared different IRs of 5.1 setup with real, mastered 5.1 programme and the loss was very significant, mainly in term of comb filtering type artifacts. So much so that I decided not to include them on my album (this was for a 5.1 release which I wanted to have the stereo reduction to be binaural) Now I know that using generic HRTF is not going to help me, but this was far worse than anything I could imagine... I presume that if I had used Ambisonic as my spacialisation device throughout the mix and composition, it would have worked better as a re-rendering... my 2 cents pa ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Sound Externalization Headphone
Junfeng Li junfeng.li.1...@gmail.com wrote: I am now researching on 3D audio playback/rendering in headphone. One purpose of this work is to playback the 5.1 Audio using headphone. One main problem for sound playback using headphone is in-head localization. Therefore to playback the 5.1 audio with headphone, I am now trying to externalize sound in headphone playback. Is anyone able to give me some comments/suggestion on this issue? There used to be the wonderful Isone Pro plug-in by Jeroen Breebaart (www.jeroenbreebaart.com) that would convert a 5.1 signal into a binaural HRTF signal for headphone reproduction in real-time. I've used it for some time for monitoring during field recording and I was quite happy with it. Unfortunately it was Windoze-only and since migrating all my audio to OS X I've been searching for a replacement. To no avail, so far. Mr. Breebaart has since released an OS X version for normal stereo signals, so I've enquired about the 5.1 version but his answer wasn't exactly encouraging. Ralf -- Ralf R. Radermacher - DL9KCG - Köln/Cologne, Germany Blog : http://the-real-fotoralf.blogspot.com Audio : http://aporee.org/maps/projects/fotoralf Web : http://www.fotoralf.de ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Sound Externalization Headphone
why should it? the virtual speaker approach is pretty much independent of your speaker spatialisation technique. this is true except when you have transients to my experience. I'll send you a short bit next week when I am back into the studio. p ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Sound Externalization Headphone
Apple's Logic software has a binaural output mode that provides a couple different panning mechanisms. Surprisingly, it works pretty well. Localization is not perfect but it does provide better depth than stereo, and the frequency domain problems are not as bad as some systems - though they do exist. I'm not a huge Logic fan, but it helped a little for mixing 5 channels to 2 (using mono stem files and panning to binaural output). I used it for the 2nd piece posted here http://jimmoses.wordpress.com/music/. jim On Wed, May 25, 2011 at 5:15 PM, Hector Centeno i...@hcenteno.net wrote: Exactly what I've been exploring using ambisonic recordings from a tetrahedral mic. I've been decoding to fixed HRTFs corresponding to virtual speakers in a cube configuration. Good to know who was doing it and when was already being done. I also made a head-tracking sensor using an accelerometer, gyroscope and magnetometer controlled by an Arduino Pro Mini: http://vimeo.com/22727528 Cheers, Hector On Wed, May 25, 2011 at 4:06 AM, Dave Malham dave.mal...@york.ac.uk wrote: On 24/05/2011 20:00, f...@libero.it wrote: snip I should mention that interpolation of HRTF is not the only possible technique; you can use for example a virtual loudspeaker array... This is certainly the way that the Lake DSP system worked that they demonstrated way back in 1993 (I think it's in the papers for the London VR93 confence from that year but I don't have my copy of the proceedings hand). The sounds were recorded in (first order) Ambisonics and the head tracking drove a rotate/tilt algorithme that fed a decoder to virtual speakers the signals from which were convolved with fixed hrtf's corresponding to the speakers' positions that were fixed wrt the head, mixed together and fed to the headphones. Dave ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound -- Jim Moses Technical Director/Lecturer Brown University Music Department and M.E.M.E. (Multimedia and Electronic Music Experiments) -- next part -- An HTML attachment was scrubbed... URL: https://mail.music.vt.edu/mailman/private/sursound/attachments/20110526/9ad1798f/attachment.html ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Sound Externalization Headphone
As in most things there are first order effects and second order effects. Although there seems to be little in the literature, the basic cause of internalization seems clearly to be interference with the pinna. You can test this for yourself by whistling and bringing your hands up to your ears. The whistle will for most people move inside their head. Thus since most earphones, interfere with the pinna internalization results. Etymotic earphones don't work because then there are no pinna. On can imagine that a brain that suddenly cannot receive any pinna directional finding patterns (or any normal ones) makes the only logical assumption possible that the sound originates inside the skull. The old IMAX helmut for 3D solved this problem (and the stereo crosstalk one) by using ear speakers. Their demo for an AES convention was very convincing. Another problem with earphone listening is that the stage is sort of always frontal, but you can get great proximity (depth) effects. The rear or overhead part, in the absence of normal Pinna function, is almost impossible to achieve unless your standards or expectations are low. You may get it to work for one listener or earphone type but not universally. Tricks like head tracking, HRTF diddling, etc. are second order fixes or mild palliatives. Pinna are like fingerprints and it is likely impossible to find a universal solution to internalization that is practical. If you measure your own pinna and then use this IR with eytmotic earphones you should get a reasonable result, but in practice this is difficult and even unpleasant. This is why the loudspeaker binaural technologies are still attractive and why there are hundreds of PC and iPod docking stations advertised. By the way the iPad app for Ambiophonics is free thanks to Steve Hotto. Ralph Glasgal glas...@ambiophonics.org www.ambiophonics.org From: Junfeng Li junfeng.li.1...@gmail.com To: Surround Sound discussion group sursound@music.vt.edu Sent: Tuesday, May 24, 2011 3:49 AM Subject: [Sursound] Sound Externalization Headphone Dear List, I am now researching on 3D audio playback/rendering in headphone. One purpose of this work is to playback the 5.1 Audio using headphone. One main problem for sound playback using headphone is in-head localization. Therefore to playback the 5.1 audio with headphone, I am now trying to externalize sound in headphone playback. Is anyone able to give me some comments/suggestion on this issue? Thank you so much in advance. Best regards, Junfeng -- next part -- An HTML attachment was scrubbed... URL: https://mail.music.vt.edu/mailman/private/sursound/attachments/20110524/e5c01522/attachment.html ___ 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/20110525/51e94c4f/attachment.html ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Sound Externalization Headphone
some months ago i acquired a battered motor cycle helmet. the aim is to mount eight loudspeakers ; remove the foam but leave the helmet suspension intact, so it is a few inches off the head in all directions. feed a standard cube decode. havent tried it yet. distracted by a loudspeaker cube! umashankar i have published my poems. read (or buy) at http://stores.lulu.com/umashankar Date: Wed, 25 May 2011 07:09:14 -0700 From: rglas...@yahoo.com To: sursound@music.vt.edu Subject: Re: [Sursound] Sound Externalization Headphone As in most things there are first order effects and second order effects. Although there seems to be little in the literature, the basic cause of internalization seems clearly to be interference with the pinna. You can test this for yourself by whistling and bringing your hands up to your ears. The whistle will for most people move inside their head. Thus since most earphones, interfere with the pinna internalization results. Etymotic earphones don't work because then there are no pinna. On can imagine that a brain that suddenly cannot receive any pinna directional finding patterns (or any normal ones) makes the only logical assumption possible that the sound originates inside the skull. The old IMAX helmut for 3D solved this problem (and the stereo crosstalk one) by using ear speakers. Their demo for an AES convention was very convincing. Another problem with earphone listening is that the stage is sort of always frontal, but you can get great proximity (depth) effects. The rear or overhead part, in the absence of normal Pinna function, is almost impossible to achieve unless your standards or expectations are low. You may get it to work for one listener or earphone type but not universally. Tricks like head tracking, HRTF diddling, etc. are second order fixes or mild palliatives. Pinna are like fingerprints and it is likely impossible to find a universal solution to internalization that is practical. If you measure your own pinna and then use this IR with eytmotic earphones you should get a reasonable result, but in practice this is difficult and even unpleasant. This is why the loudspeaker binaural technologies are still attractive and why there are hundreds of PC and iPod docking stations advertised. By the way the iPad app for Ambiophonics is free thanks to Steve Hotto. Ralph Glasgal glas...@ambiophonics.org www.ambiophonics.org From: Junfeng Li junfeng.li.1...@gmail.com To: Surround Sound discussion group sursound@music.vt.edu Sent: Tuesday, May 24, 2011 3:49 AM Subject: [Sursound] Sound Externalization Headphone Dear List, I am now researching on 3D audio playback/rendering in headphone. One purpose of this work is to playback the 5.1 Audio using headphone. One main problem for sound playback using headphone is in-head localization. Therefore to playback the 5.1 audio with headphone, I am now trying to externalize sound in headphone playback. Is anyone able to give me some comments/suggestion on this issue? Thank you so much in advance. Best regards, Junfeng -- next part -- An HTML attachment was scrubbed... URL: https://mail.music.vt.edu/mailman/private/sursound/attachments/20110524/e5c01522/attachment.html ___ 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/20110525/51e94c4f/attachment.html ___ 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/20110525/d4425826/attachment.html ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Sound Externalization Headphone
http://recherche.ircam.fr/equipes/salles/listen/sounds.html Uli Brüggemann -- next part -- An HTML attachment was scrubbed... URL: https://mail.music.vt.edu/mailman/private/sursound/attachments/20110525/9842a3d8/attachment.html ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Sound Externalization Headphone
Exactly what I've been exploring using ambisonic recordings from a tetrahedral mic. I've been decoding to fixed HRTFs corresponding to virtual speakers in a cube configuration. Good to know who was doing it and when was already being done. I also made a head-tracking sensor using an accelerometer, gyroscope and magnetometer controlled by an Arduino Pro Mini: http://vimeo.com/22727528 Cheers, Hector On Wed, May 25, 2011 at 4:06 AM, Dave Malham dave.mal...@york.ac.uk wrote: On 24/05/2011 20:00, f...@libero.it wrote: snip I should mention that interpolation of HRTF is not the only possible technique; you can use for example a virtual loudspeaker array... This is certainly the way that the Lake DSP system worked that they demonstrated way back in 1993 (I think it's in the papers for the London VR93 confence from that year but I don't have my copy of the proceedings hand). The sounds were recorded in (first order) Ambisonics and the head tracking drove a rotate/tilt algorithme that fed a decoder to virtual speakers the signals from which were convolved with fixed hrtf's corresponding to the speakers' positions that were fixed wrt the head, mixed together and fed to the headphones. Dave ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
[Sursound] Sound Externalization Headphone
Dear List, I am now researching on 3D audio playback/rendering in headphone. One purpose of this work is to playback the 5.1 Audio using headphone. One main problem for sound playback using headphone is in-head localization. Therefore to playback the 5.1 audio with headphone, I am now trying to externalize sound in headphone playback. Is anyone able to give me some comments/suggestion on this issue? Thank you so much in advance. Best regards, Junfeng -- next part -- An HTML attachment was scrubbed... URL: https://mail.music.vt.edu/mailman/private/sursound/attachments/20110524/e5c01522/attachment.html ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Sound Externalization Headphone
Dear Eero, Thanks a lot for your reply. Yeah, the headphone that you mentioned is what I am researching on. What I am wondering is how to implement this headphone technically. Which technique should be used? Is there any further information on this topic? Thank you. Cheers. Junfeng On Tue, May 24, 2011 at 3:51 PM, Eero Aro eero@dlc.fi wrote: http://www.dolby.com/consumer/understand/enhancement/dolby-headphone.html Eero ___ 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/20110524/ca314047/attachment.html ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Sound Externalization Headphone
Junfeng Li wrote: What I am wondering is how to implement this headphone technically. Which technique should be used? Is there any further information on this topic? Dolby usually has good documentation on their products, I recommend you search their website. Dolby Headphone is based on the convolution filtering technique developed by Lake in Australia. Eero ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Sound Externalization Headphone
Check this: http://smyth-research.com/products.html Daniel -Ursprüngliche Nachricht- Von: sursound-boun...@music.vt.edu [mailto:sursound-boun...@music.vt.edu] Im Auftrag von Junfeng Li Gesendet: Dienstag, 24. Mai 2011 10:00 An: Surround Sound discussion group Betreff: Re: [Sursound] Sound Externalization Headphone Dear Eero, Thanks a lot for your reply. Yeah, the headphone that you mentioned is what I am researching on. What I am wondering is how to implement this headphone technically. Which technique should be used? Is there any further information on this topic? Thank you. Cheers. Junfeng On Tue, May 24, 2011 at 3:51 PM, Eero Aro eero@dlc.fi wrote: http://www.dolby.com/consumer/understand/enhancement/dolby-headphone.h tml Eero ___ 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/20110524/ca314047/attachment.html ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Sound Externalization Headphone
Dear Jorn, well, if you have headphones, you have to be doing binaural synthesis. so what happens is you take the positions of the speakers you want to simulate, and convolve each speaker signal with the appropriate head-related transfer functions for the left and right ear. the next step (and a pretty important one) is to track the user's head movements, and at the same time crossfade to another set of HRTFs. that's not exactly trivial, but also quite well understood, and there are some free implementations that do the job pretty well. I read some scientific papers on head tracking for binaural rendering using headphone, it seems head tracking is quite important. While I did not find any implementation on it. Could you share some information on free implementation on it? that's pretty much all there is to it. in theory :) what makes it a product is to figure out how to a) either measure the customer's own HRTFs without annoying them too much (because you want quite a lot of them), or b) provide some means to select and optimize a generic set of HRTFs. iiuc, smyth is doing a). I got it in theory, especially for smyth's product. Thank you so much. Best regards, Junfeng -- 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 -- next part -- An HTML attachment was scrubbed... URL: https://mail.music.vt.edu/mailman/private/sursound/attachments/20110524/5b37313e/attachment.html ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Sound Externalization Headphone
There's a paper on the Studer BRS in here: http://www.irt.de/IRT/FuE/as/pdf/Spi19thAES%20Conf.pdf Eero ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Sound Externalization Headphone
On 24/05/11 04:49, Junfeng Li junfeng.li.1...@gmail.com wrote: Is anyone able to give me some comments/suggestion on this issue? I never really heard this strange looking contraption but, if it copes with half of what it advertises, Beyerdynamic has something that probably would interest you: http://europe.beyerdynamic.com/shop/hah/headphones-and-headsets/at-home/home -theater/headzone-home-ht.html Greetings from Brazil! Luiz Prado ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
