Kim is almost right in that it is TIME that gives us the most powerful
directional cues. Amplitude differences between ears is second. The low
pass filter to one ear and high pass to the other does both, because
there is phase shift in the spectrum where the response is falling.
The importance of time is easily demonstrated. Set up two loudpeakers as
for stereo and play the same white noise (between stations on FM) to
them. Now, get exactly on centerline between them and facing center,
listen to the sound, them crab-walk side to side so you're still facing
centerline. As you move either side, the image will very quickly shift
to the speaker you are nearest to.
Now, turn so that only one ear faces the speakers and repeat the
listening experiment as you walk normally (and slowly) back and forth
between them. You will the sound of the noise change as your ear gets to
places where certain frequencies are 180 out of phase and nearly equal.
This is the mechanism that causes selective fading (that very slow
facing on the AM band and 160 and picket fencing on the VHF/UHF bands).
It happens when an antenna picks up both a direct signal and one that is
reflected by band conditions.
73, Jim K9YC
On Wed,1/4/2017 7:08 AM, Kim Elmore wrote:
I think what you will find is that there will be no aural spatial definition.
Where we perceive sounds come from depends on a phase difference defined by
time-of-arrival and frequency. The phase difference is unique for a given
location and frequency. It's not a simple process. By simply altering the phase
as a set constant, all location information is lost and sounds appear to come
from everywhere with no focused location.
Kim N5OP
"People that make music together cannot be enemies, at least as long as the music
lasts." -- Paul Hindemith
On Jan 3, 2017, at 22:48, Spencer <w1gak@arrl.net> wrote:
Steve Ellington wrote:
Dear "Not True":
I said "SOME effect"....Not same effect.
I will try to get 90 degree phase diff in a set of headphones +45 one side, -45
other side.
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