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.com>wrote: > 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.it"<f...@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 by convolving your signals with >>>> >bursts of noise, passing them through allpass filters, applying varying >>>> >delays, whatever you can do that will scramble the phase but not the >>>> >magnitude of the sounds. >>>> > >>>> >I have heard demonstrations with room simulated binaural responses that >>>> >were well externalised without head-tracking, adding head-tracking >>>> >should be very effective. You can check the literature for audio >>>> >decorrelation techniques or artificial reverberation. Have a look also >>>> >on the following master thesis: >>>> > >>>> >Headphone Sound Externalization - TKK Acoustics >>>> >www.acoustics.hut.fi/publications/files/theses/liitola_mst.pdf >>>> > >>>> >Regards, >>>> >Archontis >>>> >>>> _______________________________________________ >>>> >>>> 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/20110602/ec5557b0/attachment.html> _______________________________________________ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
