New Scientist Question

["Susan E. Hall" <susanhal@xxxxxxxxx>]

I've always had the yawning - pitch drop effect very strongly. Also,
I can easily induce a pitch modulation at will when listening to
headphones by performing a sort of muscular tensing of something in
my ear/throat area. I guess I'm doing the middle ear contraction
mentioned by Greg O'Beirne in his original post, because it does
result in a low-pitched sensation (closer to a "roar" than a "rumble"
in my mind - it's smoother than a rumble).

Anyway, I just now performed a simple test. I listened separately to
a tone and then to some noise, and was easily able to lower the pitch
of both, equally well. Am I right in concluding that this rules out
the ear-canal filtering explanation? While it is true that the muscle
contraction I use results in a low-pitched background roar, it does
*seem* like the pitch of the stimulus is altered independently from
that, although I could be mistaken in my ability to separate the
effects. Are there any data on the effects of background noise on
pitch/frequency discriminations?

Susan Hall
Dalhousie University