Hello Dave, Thanks for the note (re the sound of vision). In addition to my hearing research, I’ve been doing a fair amount of music recording. Here in the USA, spaced pair miking is quite popular, as is isolating instruments and then positioning the instruments via panning in the final mix. I’ve gone the direction of ORTF, Blumlein, mid-side, etc. to satisfy my own interest (and create my own opinions). I absolutely love the sound I get using the Blumlein Stereo technique with ribbon (generally Royer) mics. It really comes across as natural and, in the frontal plane, rivals Ambisonic recordings I've made using a borrowed Soundfield mic. The only issue I have with the Blumlein stereo technique, at least when it comes to recording stimuli for my research, is the reversal of sound sources picked up from the rear. If I was recording a jazz quartet in front of me (as an example), and not concerned about the direction of reflections in the rear plane, this would not be a problem. But if I desire to immerse listeners in a restaurant of 3D sound, the Blumlein technique isn’t the best. My solution to date: Ambisonics.
I’d use binaural recordings and matching HRTFs to subjects, but the problem here is that of fitting headphones over hearing aids or CIs. I guess what I’m ultimately after is the equivalent *HRFT* in the soundfield, and one that allows free head movement. The sweetspot doesn’t have to be large, as I don’t anticipate subjects to be bouncing around (parent consent isn't the only reason for not using children). I’m definitely against putting people’s head in a restraint (bit bar or whatever) because head movements are a part of natural listening. When I refer to stereo as an illusion, I’m usually referring to the arrival time and SPL of two identical sounds emanating from separate (L + R) loudspeakers as being equal. The resulting acoustic wave or waves at the listener's head aren’t the same as the physical wave originating from a speaker located directly ahead of the listener. I’m fairly sure it’s mostly the brain’s integration of info, not physical waveform superposition, that gives the illusion that the sound is coming from inbetween the L & R speakers. In one of my studies that ultimately got published in Noise & Health, the stimulus sounds came from individual speakers--I didn't have to worry about wave field reconstruction. In that study, pinnae cues certainly turned out to be valuable for locating complex sounds: When ILDs and ITDs were maintained, but the pinnae obscured, localization errors weren’t ambiguous (judged by response time) but nearly always in error (the errors were front-back judgments, never lateralization errors). With regard to your suggesting an anechoic environment with a standardized HOA speaker array and direct sounds coming from individual speakers: That’s pretty much what I’m shooting for! Oticon appears to be using a HOA system with (I believe) 29 speakers. But because I want to use field recordings of restaurants or similar venues, I’d need a HOA mic. Anybody out there used the Eigenmic, or know where I could get a sample recording made with one? Other suggestions?? I guess the good news is that my research isn’t costing taxpayers money or hurting anyone. It’s probably odd that I made hearing research something of a hobby: All of the work I do is self-funded and not-for-profit. I always have unanswered questions (and the list grows). But once I get things in place and do a pilot study, I’ll invite a few prominent researchers over to scrutinize my setup. I gave a colloquium some years back, and it mostly ended up with professors (and department heads) arguing with each other. But despite that ordeal, a few ideas came to fruition, and I ended up getting a research award from the American Academy of Audiology. That was a good spring board for what I wish to accomplish next. I really appreciate that people put their time and thought into this list, and are patient enough to help someone like me. Thanks again, Eric -------------- next part -------------- An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20120604/4de27eaf/attachment.html> _______________________________________________ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
