Hello Haig, Thank you very much for the note and for the link (below). Gathering from my research and from what I’ve read over the years, pitch discrimination is difficult for cochlear implant (CI) recipients, thus making music enjoyment... well... not so enjoyable. As the video states, we take our ability to discern pitch for granted. I hope other will view the video/doc. In case other readers didn’t see your post, I’ve provided the link to the concert you recorded: http://www.abc.net.au/arts/stories/s3051873.htm A friend of mine (Louise Loiselle) received a grant from the NIH as well as funding from Med-El (Austria) to research localization ability for bilateral (or bi-modal) CI patients. Her doctoral committee includes world-renowned hearing scientists Bill Yost (who's well-known in psychoacoustic circles) and Michael Dorman (who heads one of the world’s leading CI labs). I’m guessing Michael is aware of the CI music you recorded, but I’ll forward the link to Louise, Bill, and Michael. Others I know who will be interested in Robin Fox's composition include Drs. Chris Brown and Sid Bacon. It is because of my interest in creating virtual listening environments for studying CI efficacy in noise that I stumbled upon Ambisonics (and I've since added Ambisonics to music-recording arsenal).
One question I had asked myself not too long back was where to “insert” a CI simulator when using normal-hearing listeners. When listening in a surround of sound, vocoding* the signal going to the individual speakers (8 feeds in my octagonal setup) doesn’t make much sense. However, Ambisonic recordings could once again help because I can rotate virtual mics in 3D environments using the B-formatted files created from live recordings. A virtual (monaural)) mic can represent a CI mic (akin to a hearing aid mic), and the signal picked off the mic can be routed through a CI simulator/vocoder. This signal, in turn, ultimately goes to my (calibrated) ER-3A insert phones, L or R. This may seem trivial, but two microphones, properly spaced (similar to ORTF placement), allows me to simulate bilateral CI listening in a 3D environment. Again, the bilateral (versus binaural) signal is presented to the subject via ER-3A insert phones. The two channels (L & R) can be individually processed, which would be the case for bilateral CI users. Bimodal (electric and acoustic) modelling is also possible. I use CI Sim software that was developed at the University of Granada, and another CI simulator developed by Dr. Qian-Jie Fu. Maybe some other readers have a better way to do this, or have presented CI-simulated sounds acoustically through a loudspeaker array? Anyway, I’m rambling now... Always a lot of ideas and thoughts (to include a couple of worthwhile ones). Many thanks again for the link! Best regards,Eric *CI simulators are, for the most part, specialized tone or noise vocoders. Envelope extraction can vary (e.g., half- or full-wave rectification with appropriate time constants or via a Hilbert transform), and the number of output channels varies depending on the number of virtual electrodes being simulated. A large (> 12) electrode count doesn't significantly improve speech understanding, and narrowing each channel's bandwidth may not improve frequency discrimination (narrowing the bandwidth works for normal-hearing listeners, but realistic simulations provide broad- or narrow-band noise, not pure tones, on the output channels). These are just a few of many variables. -------------- next part -------------- An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20120407/cf90ca9b/attachment.html> _______________________________________________ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
