I want to see a good quality over the ear stereo headphone with all necessary electronics built into the headband. It will have single usb connector which will provide power and digital audio (24 bit) and carry head tracking information back to the computer, which will have the software to play standard first order B-format files decoded to binaural, using simple HRTF filters. The computer can be your desktop, a tablet computer or a mobile.
umashankar Sent from Mail<https://go.microsoft.com/fwlink/?LinkId=550986> for Windows 10 From: Stefan Schreiber<mailto:st...@mail.telepac.pt> Sent: Sunday, January 31, 2016 1:28 AM To: rica...@justnet.com.au<mailto:rica...@justnet.com.au>; Surround Sound discussion group<mailto:sursound@music.vt.edu> Cc: Aaron Heller<mailto:hel...@ai.sri.com> Subject: Re: [Sursound] Never do math in public, or my take on explaining B-format to binaural Richard Lee wrote: >Just to bring everyone down to earth .. > >There are two easily reproduced experiments first carried out by prominent >members of this group which put these effects into perspective. They are >the > >Greene/Lee Neckbrace >and >Malham/Van Gogh Experiment > >The first shows 'real life' Fixed Head Localisation (which matched HRTFs >address) is TERRIBLE. Many people can't even distinguish back/front with >perfect (measured on their own noggin) HRTFs ... or even in 'real life' >with a Greene/Lee neckbrace. Anyone who has done fixed head localisation >experiments finds this out real quick. > >The second shows that even the tiniest amount of head movement improves >localisation immensely and any ambiguity due to mismatched Pinnae etc (and >YES, the pinnae colouration effects are chaotic) are INSTANTLY resolved. > No 'training' is necessary with head movement. > > https://mediatum.ub.tum.de/doc/1207048/1207048.pdf > The bottleneck for an immersive binaural sound synthesis is the > acquirement of individual > Head-Related Transfer Functions (HRTF). Manifold HRTF approaches to > circumvent the > obstacle of HRTF measurement are topic in research. The localization > performance of three > more or less individualized HRTF-datasets is related to the > individually measured HRTF. An > intuitive experimental design, using laser pointing for indicating the > perceived sound source > direction, is introduced to evaluate those individualization > approaches. Besides the impact of > head-tracking is investigated. The results show that the azimuth > localization error does not > differ significantly for an generic dummy-head HRTF, the individually > measured HRTF and > the HRTF selected from a certain set of other person’s HRTFs, if > head-tracking is available. > In the case without head-tracking the measured HRTF grants the > smallest reversal rate. This > results can be taken into account for designing an binaural auditory > application ... > In general the mean localization error for all data is comparable to > prior researches. > < Considering the results for the elevation localization, it was found > that the performance is > significantly better for the noise stimuli and also for the individual > HRTF. In general the > elevation directions were underestimated. > ... > For the HRTF-sets it can be stated that head-tracking reduces the > differences in localization > error. < No significant differences between measured HRTF, KEMAR HRTF > and selected > HRTF for the azimuth error could be found. > In contrast to that the > differences in the means > of the azimuth error are significant for all HRTF-datasets if > head-tracking is not available, > whereas the lowest error was obtained using the individually measured > HRTF. Thanks (very obviously) to the Technical University of Munich, which still "dares" to publish research which is funded by the tax payer. (More and more universities seem to be bound by NDA agreements, even if participating companies don't contribute anywhere to 50% or more to the costs.) At 1st reading, R. Lee seems to have some support... It could be that we still need personalised HRTFs, in spite of HT. (Elevation cues; spectral/pinna cues needed for localisation in the median plane.) Best, Stefan >Even vertical localisation, for which Fixed Head HRTFs have the most >benefit, require a priori knowledge of the source spectrum. I've done a >small amount of work involving victims ... I mean subjects ... blindfolded >and tied up face down on anechoic chamber floors which show the first pin >drop is impossible to localise. Second and subsequent pin drops are much >easier. > >I'll point out that Gerzon had Fixed and Moving Head versions of all his >Localisation Theories. The infamous Energy and Velocity vector >'magnitudes', rE & rV, are in fact a measure of the correspondence of Fixed >with Moving. > >His Energy and Velocity models incorporate (give the same results as) ALL >the existing Localisation models except for the HF interaural delay >(Transient) and Colouration ('HRTF') models. > >One of Gerzon's most important contributions is that he shows the >equivalence of the full Moving Head models like Makita, which assume the >listener will fully turn to face the sound ... with the models that only >assume small involuntary head movements. See "General Metatheory ... " for >the nitty gritty. >____________________ > >If you make some B-format recordings with a properly aligned Ambisonic mike >like TetraMic, you can test some of this for yourself. Have lots of things >happening all around including up & down. Use headphones and the crudest >possible Binaural decoding ... slightly hyper cardioids at about 150. > >You will find about 10% of the population have difficulty with front/back. > But let these guys twiddle the Azimuth & Elevation controls on VVMic >themselves and they immediately become happy with the scene ... even before >they work out VVMic's slightly quirky interface. >____________________ > >CONCLUSIONS > >If you have Head Tracking (ie Moving Head Localisation), don't bother with >fancy HRTFs. > >Eric Benjamin found that you get most of the benefits from just getting >head size right but even this isn't necessary if you have Head Tracking. > Blumlein shuffle probably worth doing as you essentially get it free with >your simple IIR implementation. > >Fancier HRTFs will need EVIL FIRs to be of use. You will lose any chance >of 'real time' and muck up the experience for 'mismatched' listeners. > Expect only small (if any) 'improvement' for the huge extra.computing load >to interpolate between HRTFs. > >If you haven't got Head Tracking, GOTO Head Tracking > >This covers all the Virtual Reality applications. The Video Game people >like Simon Goodwin of Codeworks have been doing it for at leas a decade >with 3rd Order HOA IIRC. > >If you insist on fancy HRTFs and Fixed Head ... do you seriously think you >can improve on the listening experience of present & past generations of >listeners, who have listened to 'music' over ear buds for more than a >decade ... with fancy HRTFs ? GOTO Head Tracking. >____________________ > >SPECIAL OFFER > >Send $500 in used bank notes to me at Cooktown Recording and Ambisonic >Productions mentioning Sursound, for a sample Greene/Lee Neckbrace and >Diamond Encrusted Malham/Van Gogh cap. Golden Pinnae are an extra cost >option on the last item. No Confederate money please. >_______________________________________________ > > > > _______________________________________________ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, edit account or options, view archives and so on. -------------- next part -------------- An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20160131/912994d7/attachment.html> _______________________________________________ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, edit account or options, view archives and so on.
