RE: ears (and links)

[Laurie Hatch <lahatch@dnai.com>]

Hey Kim, gracias for elaborating on Darwin's page.  Without your 
interpretation, I doubt I would have plucked this from the maze with the 
recognition that it was a piece to the puzzle.

Cool that Wessel materialized at such an opportune time - again, thanks 
for 
asking the questions, and for taking the time to relay his responses.

laurie

 Kim wrote:
On this fellow's excellent page may be part of the answer, specifically 
here:
http://www.biols.susx.ac.uk/Home/Chris_Darwin/Perception/Lecture_Notes/Heari
  
ng3/hearing3.html#RTFToC6

where he discusses combination tones.
a summary:
In a person with healthy hearing, when two tones fairly close in frequency 
are 
played, a third tone can be heard. If the two input tones are F1 and F2, 
the 
third tone will be 2F1 - F2. This is called the cubic difference tone.
This will probably not be harmonically related to either tone, and will 
therefore could sound very dissonant. He also notes that people suffering 
from 
hearing loss will not experience this. (he explains why, go read it.)
By coincidence, I saw David Wessel tonight and asked him if he knew an 
answer, 
and he mentioned this same effect as a possibility. (he also noted there 
is 
much debate on the subject, and there are no hard answers.)  He also noted 
that 
in older population groups, men usually suffer from considerably more 
hearing 
loss than women. (it's not clear if this is due to lifestyle, which may 
therefore be changing, or physiological differences.) So men will have 
more 
hearing loss than similarly aged women, and therefore will not experience 
this 
third tone effect as much as women will. So maybe that's part of the 
answer.
As to why these dissonances result in discomfort, I have no idea.....
kim
________________________________________________________
Kim Flint                      408-752-9284
Mpact System Engineering       kflint@chromatic.com
Chromatic Research             http://www.chromatic.com



>From lists@slip.net Fri Mar 13 10:26:14 1998