Hello Eric, Many thanks for the link to Knowles' miniature mics, as that is more current than the HA mic articles (e.g. Killion et al) I have on file. Clearly, such mics aren't intended to compete with Neumann, Schoeps, etc. studio mics, but their performance is quite amazing for such tiny mic elements! And their miniscule size might make them entirely suitable for multi-element "point source" mics, too. Boosting the low end, as you pointed out, certainly has a deleterious effect on noise performance. Although F0 (first formant) isn't needed for intelligible speech--at least for normal-hearing persons--it does find an important purpose in EAS (electric-acoustic stimulation) devices. Briefly, persons with profound hearing loss (but with residual low-frequency hearing) have poor speech comprehension using only their low-frequency hearing. Cochlear implant (electric) hearing yields modest speech scores for many of these persons. But when the low-frequency (acoustic) hearing is added to electric stimulation, the combined results are amazingly good--much better than what researchers might have anticipated. One of the earlier problems was preserving low-frequency hearing while implanting an electrode array. Nowadays, shallow electrodes are implanted in order to preserve low-frequency hearing (note: a hearing aid is still needed to boost the low frequencies).
Questions, of course, remain, and it will be useful to study the effects of EAS in reverberant conditions and a variety of noise types. Whether the mic used to boost the low frequencies (conventional amplification) should be omni or directional may not be clear, and same goes for the mic or mics used to process the mid and high frequencies. As you had also pointed out, there's a head-mic interaction, and this must be considered. After all, we're looking at a system, and a holistic approach is my objective. Although not every possible variable can be accounted for, it doesn't hurt to try a few representative scenarios that a CI recipient would encounter. The ability to hear and discern warning signals (and their direction) or moving vehicles can be studied. Restaurants, Houses of Worship, and classrooms are typical listening environments, and Ambisonic recordings certainly provide opportunity to re-create acoustic events over and over again in a controlled, repeatable manner. Even without loudspeakers, I believe it is feasible to study mic directionality when using Ambisonic recordings. Combining mic polar characteristics with HRIRs is the next step. Thanks for reading my posts, and for taking time to share you wisdom. Best, Eric -------------- next part -------------- An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20121110/9ba1b1bf/attachment.html> _______________________________________________ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
