Hello All, First, many thanks for taking time to read this. This may be one of my better attempts at communicating what I’m attempting to do. I very much appreciate and respect all the input regarding human perception (re prior posts / the sound of vision).
Professor Robert Greene wrote *...But right now, no one can know what anyone else experiences except in some structural sense.* I fully agree, but we (experimenters, psychologists) would have to provide the same physical stimulus for participants to agree on what *red” is. This means that light reflecting off of the *red* object contains the electromagnetic wavelengths requisite for stimulating the retinal cones (and rods too?) and eliciting a perception of the colour red (or the light itself is could be *red* by physical definition). Same goes for audio stimuli. I believe it would be interesting to study how the hearing impaired *hear* reverberation. Have you listened to the Scottish prayer example that is often used in classroom demonstrations? This so-called “ghoulies and ghosties” demonstration (found on the “Harvard tapes”) has become somewhat of a classic. The recording is of a hammer striking a brick followed by an old Scottish prayer. The reader is Dr. Stanford Fidell. Playing the recording backwards focuses our attention on the echoes. Practically no one reports hearing echoes in small (although reverberant) spaces when a transient sound is initiated. The echoes are not *heard* although the reflected sound may arrive as much as 30 to 50 ms later. The Scottish prayer demonstration is designed to make the point that these echoes do exist and are appreciable in size. Our hearing mechanism somehow manages to suppress the late-arriving reflections, and they go unnoticed (at least for the majority of us). There is reason to believe that hearing-impaired persons have greater difficulty suppressing reverberation (a central processing issue, not necessarily peripheral organ dysfunction??). Hearing and consciously perceiving these echoes could, then, impart a deleterious effect on word recognition ability. But without providing the same physical stimulus to the hearing impaired listener, can we determine the magnitude of effect? If the recording of the hammer (transient) is perceived as being the same regardless whether it is played in reverse or not, we can make inferences regarding echo suppression. But if the recording used for one population (normal-hearing listeners) is not identical to the recording used to study a different population (e.g. hearing-impaired listeners), what initial inferences can we make about the latter’s perception under reverberant conditions? A recording / playback system that includes echoes coming from multiple directions could provide additional insight (and real-world validity). All I’ve been saying is that the one variable that can be controlled is the physical stimulus. Stimuli that represent real-world scenarios have more external validity than tightly controlled sounds made up of monaural buzzes, clicks or tones. Similarly, it’s relatively easy to build and program a robot that can navigate in a virtual world built around well-defined colors, blocks and shapes; understanding how we navigate in the real (complex) world requires more complex stimuli (e.g. Rodney Brooks’ robots successfully navigate over difficult terrain without a priori info about the environment). We will never know what these robots are *thinking* (some don’t even run on code), but we can still measure their performance and then find ways to improve on the design. I wish to improve hearing aid and cochlear implant design; consequently, I need physical stimuli that represent the world outside of the laboratory. This has been my impetus for exploring Ambisonics. Naturally, I'm greatly enjoying the musical / artistic aspects of Ambisonics as well. Kind regards, Eric -------------- next part -------------- An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20120606/e4f83d8b/attachment.html> _______________________________________________ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
