Acoustic effects of human external ear helix?

[Salmon Egg]

I have posted before on the effect of using hands cupped over my ears
to improve speech intelligibility. I just noticed that placing my
forefingers onto the ear helix valleys while not covering the ear canal
has a significant effect on the perceived frequency distribution. Almost
everything I do of that nature appears to improve intelligibility. Has
anyone studied this effect?

My advancing years may be a reason for poorer intelligibility, but I do
not think that that is the whole story. My guess is the shape of the
helix is an evolutionary development to better adapt to the environment.

bill

[glen herrmannsfeldt]

Post by Salmon Egg
I have posted before on the effect of using hands cupped over my ears
to improve speech intelligibility. I just noticed that placing my
forefingers onto the ear helix valleys while not covering the ear canal
has a significant effect on the perceived frequency distribution. Almost
everything I do of that nature appears to improve intelligibility. Has
anyone studied this effect?
My advancing years may be a reason for poorer intelligibility, but I do
not think that that is the whole story. My guess is the shape of the
helix is an evolutionary development to better adapt to the environment.

The shape is needed for the second dimension of direction detection.

The time difference between arrival of a sound gives you one
dimension for direction detection, but you need two. That comes
from the change in frequency distribution.

-- glen