And, of course, it would be essential to test for the effects of age on the rapidity of change, so I guess I will be forced to come out of retirement in order to provide a suitable subject without inconveniencing anyone else...
Dave On 6 November 2012 11:09, Peter Lennox <[email protected]> wrote: > well, I think it's a big jump, so to speak to try to get funding for that. > > I have a much more modest proposal: > > Is auditory spatial perception and performance similar in all regions? - I > have a strong suspicion that it's different in the Maldives. Further, I think > it may be that, if you take someone that has been tested in, say, England, > then transport them to the Maldives and test, looking for changes in > performance over a 2 month period, one might find a progressive change. Then > bring them back for a two month, repeating the test procedure. Then back to > the Maldives, testing if the change in performance is similar, or indeed more > rapid, the second time around. > If significant results are obtained, we next try Bali. and so on. > This will be much cheaper than the zero-G proposal > > In the interests of science, I am prepared to volunteer as a guinea pig, even > if it means turning my back on my chances of being promoted to fourth > assistant to the deputy office manager - that's how dedicated to science I am! > Dr Peter Lennox > > School of Technology, > Faculty of Arts, Design and Technology > University of Derby, UK > e: [email protected] > t: 01332 593155 > ________________________________________ > From: [email protected] [[email protected]] On Behalf > Of Dave Malham [[email protected]] > Sent: 05 November 2012 16:28 > To: Surround Sound discussion group > Subject: Re: [Sursound] Vestibular response, HRTF database, and now with > added height... > > Hi Peter, > Like I just said - needs experiments in zero G. I wonder what the > acoustics in the ISS are like? Might be easier to organise decent > acoustics in a Vomit Comet > (http://en.wikipedia.org/wiki/Reduced_gravity_aircraft) especially as > the padding already there would help. Now, where do we apply for > funding?? > > Dave > > On 5 November 2012 14:18, Peter Lennox <[email protected]> wrote: >> Eric, some interesting thoughts there, thanks. >> One or two thoughts in reaction: >> 1) you say " There have been a lot of studies regarding localization in the >> transverse (horizontal) plane" - I know its quite common to conflate these, >> but (as implied in your later thought experiment) - it's worth pointing out >> that "horizontal" is specified as perpendicular to gravity. When a person is >> standing or sitting straight, then if the head is not tilted then the >> conflation is permissible. But. People tilt and move their heads all the >> time, so acuity in hearing in the transverse plane is not the same as acuity >> in the horizontal plane >> >> 2) Your question about acuity when the body is not in that 'usual' >> orientation: I've thought the same thing, though the other way around - I >> put people flat on their backs, then played ambisonic material tilted >> through 90 degrees, to see if they got some different experience. So, I was >> interested in perception in the vertical, but using that transverse plane. >> The experience was different, but inconclusive in that it wasn't a >> controlled experiment, of course. I found that identification of source >> direction was less good than I'd anticipated. BUT - actually, (going back to >> experiences whilst camping - I've lain awake in the countryside thinking >> about these things) - listening (especially for direction) with your head so >> close to the ground is certainly an unfamiliar experience. You've messed up >> a lot of the pinnae effects. Interaural differences may well be affected. >> You've got a peculiar pattern of very early reflections (from the ground >> next to your ears). Most importantly , > y >> ou're listening to sources in the sky, with no reflective and occlusive >> bodies around them. There's no 'ground effect' of the sort that a standing >> or sitting person will get - that it, early reflected material that has >> interacted with the ground, including filtering by surface features, clutter >> (material objects and detritus have a tendency to be near the ground due to >> gravity...) so, overall, hearing in that area just won't be the same. >> The above might partly account for why, in your experiment, hearing in the >> horizontal might seem better than it ought - there are simply more cues >> available for sources at or near the ground? However, in the camping >> example, I did find increased instances of reversals. >> >> So I had thought there might be an interaction between gravity and spatial >> hearing, but realised that some of it is just down to physics - the sky >> really is different from the ground, we really are sort of "2.5 d" hearers >> (and thinkers?). I'd also wondered whether distance(range) perception might >> differ with direction. It does (items seem nearer), but more to do with the >> physics of the matter - for sources in the sky, sometimes (not always!) >> there is only a direct signal path. So, distance perception as the product >> of the direct/indirect ratio doesn't seem quite the right formulation. >> >> These things need some decent experimentation, it seems to me >> >> Cheers >> ppl >> >> >> Dr. Peter Lennox >> >> School of Technology, >> Faculty of Arts, Design and Technology >> University of Derby, UK >> e: [email protected] >> t: 01332 593155 >> >> -----Original Message----- >> From: [email protected] [mailto:[email protected]] >> On Behalf Of Eric Carmichel >> Sent: 03 November 2012 18:54 >> To: [email protected] >> Subject: [Sursound] Vestibular response, HRTF database, and more >> >> Greetings, >> Mostly through serendipity, I have had the pleasure and privilege of great >> teachers. I studied recording arts under Andy Seagle (andyseagle.com) who >> recorded Paul McCartney, Hall & Oats, and numerous others. My doc committee >> included Bill Yost, who is widely known among the spatial hearing folks. >> And, of course, I've learned a lot about Ambisonics from people on this list >> as well as a plethora of technical articles. >> >> I recently sent an email to Bill with the following question/scenario. I >> thought others might wish to give this thought, too, as it gets into HRTFs. >> >> There have been a lot of studies regarding localization in the transverse >> (horizontal) plane. We also know from experiments how well (or poorly) we >> can localize sound in the frontal and sagittal planes. By simply tilting >> someone back 90 degrees, his/her ears shift to another plane. This is >> different from shifting the loudspeaker arrangement to another plane because >> the semicircular canals are now in a different orientation. If a circular >> speaker array was setup in the coronal plane and the person was lying down, >> then his/her ears would be oriented in such a way that the speakers now >> circle the head in the same fashion as they would in the horizontal plane >> when the person is seated or standing. It's a "static" vestibular change, >> and gravity acting on the semicircular canals (and body) lets us know which >> way is up. But do we have the same ability to localize when the body is >> positioned in different orientations, even when the sources "follow" the >> orientation (as is the case > in >> the above example)? How about localization in low-g environments (e.g. >> space docking)? The question came to me while camping. I seem able to >> pinpoint sounds quite well in the (normal) horizontal plane despite a skewed >> HRTF while lying down (and somewhat above ground). >> >> On another (but related) topic, I have downloaded the HRTF data from the >> Listen Project, and have been sorting the participant's morphological >> features. I have this in an Excel spreadsheet, and am converting this to an >> Access database. Using the data, one can pick an "appropriate" HRTF starting >> with gross anatomical features (such as headsize) and whittle it down to >> minute features (such as concha depth or angle). I find HRTF discussions >> interesting, but still argue that headphones and whole-body transfer >> functions make a difference, too. Insert phones destroy canal resonance, >> whereas an earcup with active drivers may have a large "equivalent" volume, >> thus minimizing external meatus/earcup interaction (a mix and match of >> resonances). Because of this, there can be no ideal HRTF, even when it >> matches the listener. >> >> While listening to HRTF demos, the notion of auditory streaming and auditory >> scenes came to mind. Some sounds were externalized, but other sounds of >> varying frequencies, while emanating from the same sound source, appeared in >> my head. The end result was that the externalized sounds provided a >> convincing (or at least fun) illusion, but problems do persist. A stringent >> evaluation of HRTF / binaural listening via headphones would require >> breaking the sounds into bands and seeing if a sound's constituent >> components remain outside of the head. When doing so, a brick-wall filter >> wouldn't be necessary, but a filter that maintains phase coherency would be >> recommended. The demo I refer to was that of a helicopter flying overhead. >> Though I haven't done this (yet), it would be interesting to use FFT >> filtering to isolate the turbine whine (a high-pitched sound) from the >> chopper's blades. The high-pitched sound appeared to be in my head, whereas >> the helicopter as a whole seemed extern a > li >> zed. Again, an individualized HRTF and different phones may yield different >> results. Side note: Be careful using FFT filtering--it can yield some >> peculiar artifacts. >> >> I am hoping to use headtracking in conjunction with VVMic to model different >> hearing aid and cochlear implant mics in space. This offers the advantage of >> presenting real-world listening environments via live recordings to >> study/demonstrate differences in mic polar patterns (at least first-order >> patterns) and processing without the need for a surround loudspeaker system. >> In fact, it's ideal for CI simulations because an actual CI user never gets >> a pressure at the eardrum that then travels along the basilar membrane, >> ultimately converted to nerve impulses. With VVMic and HRTF data, I should >> be able to provide simulations of mics located on a listener's head and then >> direct the output to one or both ears. This does not represent spatial >> listening, but it does represent electric (CI) hearing in space. Putting a >> normal-hearing listener in a surround sound environment with mock processors >> and real mics doesn't work because you can't isolate the outside (surround) >> sound from the i > nt >> ended simulation, even with EAR foam plugs and audiometric insert phones. >> VVMic and live recordings via Ambisonics is a solution to creating >> "electric" listening in the real world. Again, I'm referring solely to CI >> simulations. With the advent of electric-acoustic stimulation (EAS), more >> than one mic is used per ear: One for the CI and a second for the HA. >> Combinations of polar patterns can be created. Respective frequency >> responses and processing can be sent to one or two ears (diotic and dichotic >> situations). One caveat for using vocoding to mimic CIs is that the acoustic >> simulation (and therefore stimulation) still necessitates a traveling wave >> along the normal-hearing listener's basilar membrane. The time it takes to >> establish a wave peak is not instantaneous (though compressional waves in >> the the inner ear are virtually instantaneous), and I believe a time-domain >> component to inner ear (mechanical) action can't easily be excluded when >> using "acoustic" simulation of CIs. I suppose I could look at data from >> BAERs and the Greenwood approximati o > n >> to account for the time-frequency interaction. Just some thinking... and >> ideas to share with others interested in hearing impairments. >> >> >> By the way, Teemko, if you're reading this, just wanted to let you know that >> Bill Yost said he'd read your thesis over the weekend. I notice that Bill >> and Larry Revit are in your references list. Larry isn't a fan of >> Ambisonics--said to me in a phone communication that it sounds "tinny". I >> suppose it does if one were to listen through laptop speakers or from poor >> source material. Not sure what his source was. >> -------------- next part -------------- >> An HTML attachment was scrubbed... >> URL: >> <https://mail.music.vt.edu/mailman/private/sursound/attachments/20121103/837528f1/attachment.html> >> _______________________________________________ >> Sursound mailing list >> [email protected] >> 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 [email protected]. >> _______________________________________________ >> Sursound mailing list >> [email protected] >> https://mail.music.vt.edu/mailman/listinfo/sursound > > > > -- > As of 1st October 2012, I have retired from the University, so this > disclaimer is redundant.... > > > These are my own views and may or may not be shared by my employer > > Dave Malham > Ex-Music Research Centre > Department of Music > The University of York > Heslington > York YO10 5DD > UK > > 'Ambisonics - Component Imaging for Audio' > _______________________________________________ > Sursound mailing list > [email protected] > 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 [email protected]. > _______________________________________________ > Sursound mailing list > [email protected] > https://mail.music.vt.edu/mailman/listinfo/sursound -- As of 1st October 2012, I have retired from the University, so this disclaimer is redundant.... These are my own views and may or may not be shared by my employer Dave Malham Ex-Music Research Centre Department of Music The University of York Heslington York YO10 5DD UK 'Ambisonics - Component Imaging for Audio' _______________________________________________ Sursound mailing list [email protected] https://mail.music.vt.edu/mailman/listinfo/sursound
