On Wed, 28 Jan 2004 00:22:04 +0100, Peter Larsen
wrote:

CJT wrote:

Clearly there is some level of delay that is totally undetectable.
After all, nerves are electrochemical devices that have a finite
response time.

This is not about processing time time, obviously there is a 0.1 second
delay in the senses (shortest human reaction time is 0.2 second), it is
about difference in time of arrival.

Beyond that, additional delay will result in an apparent shift of
the stereo center.

The issue is exactly at what time offset the shift gets apparant and/or
obvious, not whether it happens.

---
That should be fairly easy to determine.

I'd simultaneously trigger two identical pulse generators driving
identical tweeters placed some distance (10 feet?) from the subject and
coaxial with their ears. If the distances were equal and the tweeters
were in phase and hit with a sharp pulse at the same time, then the
subject should hear a click in the center of his head. If, then, one of
the pulses was delayed, the subject should perceive the click as moving
toward the other speaker.

I've got an old HP222A pulse generator, and to test the concept I drove
two piezo tweeters simultaneously with a 200µs wide pulse at a rep rate
of about 6pps, then separated the tweeters by about 3 feet and stuck my
head in between them so they were pointing right at my ears, one on each
side. I could _clearly_ position my head between them to make it seem
like the click was centered in my head, and then just moving my head
_very_ slightly (a couple of inches) back and forth made the apparent
position of the pulse change. If anybody's interested I can set up a
double-pulse experiment and take some data...

--
John Fields

Clearly there is some level of delay that is totally undetectable.
After all, nerves are electrochemical devices that have a finite
response time.

Beyond that, additional delay will result in an apparent shift of
the stereo center.

What I wanted to say: no time difference is acceptable because of a) the
stereo center shift, b) possible frequency erasements, and c) the human ear
is able to detect time differences of ~10ms (that is 0,01 sec) as a delay!

Sorry for my lousy English... you know now what I mean?

Regards,
Olaf

Clearly there is some level of delay that is totally undetectable.
After all, nerves are electrochemical devices that have a finite
response time.

Beyond that, additional delay will result in an apparent shift of
the stereo center.

What I wanted to say: no time difference is acceptable because of a) the
stereo center shift, b) possible frequency erasements, and c) the human ear
is able to detect time differences of ~10ms (that is 0,01 sec) as a delay!

Sorry for my lousy English... you know now what I mean?

Regards,
Olaf

Clearly there is some level of delay that is totally undetectable.
After all, nerves are electrochemical devices that have a finite
response time.

Beyond that, additional delay will result in an apparent shift of
the stereo center.

What I wanted to say: no time difference is acceptable because of a) the
stereo center shift, b) possible frequency erasements, and c) the human ear
is able to detect time differences of ~10ms (that is 0,01 sec) as a delay!

Sorry for my lousy English... you know now what I mean?

Regards,
Olaf

Clearly there is some level of delay that is totally undetectable.
After all, nerves are electrochemical devices that have a finite
response time.

Beyond that, additional delay will result in an apparent shift of
the stereo center.

What I wanted to say: no time difference is acceptable because of a) the
stereo center shift, b) possible frequency erasements, and c) the human ear
is able to detect time differences of ~10ms (that is 0,01 sec) as a delay!

Sorry for my lousy English... you know now what I mean?

Regards,
Olaf

On Wed, 28 Jan 2004 10:24:48 +0100, Olaf Roß wrote:

Clearly there is some level of delay that is totally undetectable.
After all, nerves are electrochemical devices that have a finite
response time.

Beyond that, additional delay will result in an apparent shift of
the stereo center.

What I wanted to say: no time difference is acceptable because of a) the
stereo center shift, b) possible frequency erasements, and c) the human ear
is able to detect time differences of ~10ms (that is 0,01 sec) as a delay!

Sorry for my lousy English... you know now what I mean?

---
Your English is fine; don't worry about it.

The human ear can detect arrival time differences far smaller than 10ms,
as I indicated in an earlier post. I was able to detect perceived
changes in the location of the source of an acoustic "click" in as
little as 2 inches, but even saying six inches (just in case...) that
comes out to less than 500 _micro_ seconds!

--
John Fields

On Wed, 28 Jan 2004 10:24:48 +0100, Olaf Roß wrote:

Clearly there is some level of delay that is totally undetectable.
After all, nerves are electrochemical devices that have a finite
response time.

Beyond that, additional delay will result in an apparent shift of
the stereo center.

What I wanted to say: no time difference is acceptable because of a) the
stereo center shift, b) possible frequency erasements, and c) the human ear
is able to detect time differences of ~10ms (that is 0,01 sec) as a delay!

Sorry for my lousy English... you know now what I mean?

---
Your English is fine; don't worry about it.

The human ear can detect arrival time differences far smaller than 10ms,
as I indicated in an earlier post. I was able to detect perceived
changes in the location of the source of an acoustic "click" in as
little as 2 inches, but even saying six inches (just in case...) that
comes out to less than 500 _micro_ seconds!

--
John Fields

On Wed, 28 Jan 2004 10:24:48 +0100, Olaf Roß wrote:

Clearly there is some level of delay that is totally undetectable.
After all, nerves are electrochemical devices that have a finite
response time.

Beyond that, additional delay will result in an apparent shift of
the stereo center.

What I wanted to say: no time difference is acceptable because of a) the
stereo center shift, b) possible frequency erasements, and c) the human ear
is able to detect time differences of ~10ms (that is 0,01 sec) as a delay!

Sorry for my lousy English... you know now what I mean?

---
Your English is fine; don't worry about it.

The human ear can detect arrival time differences far smaller than 10ms,
as I indicated in an earlier post. I was able to detect perceived
changes in the location of the source of an acoustic "click" in as
little as 2 inches, but even saying six inches (just in case...) that
comes out to less than 500 _micro_ seconds!

--
John Fields

On Wed, 28 Jan 2004 10:24:48 +0100, Olaf Roß wrote:

Clearly there is some level of delay that is totally undetectable.
After all, nerves are electrochemical devices that have a finite
response time.

Beyond that, additional delay will result in an apparent shift of
the stereo center.

What I wanted to say: no time difference is acceptable because of a) the
stereo center shift, b) possible frequency erasements, and c) the human ear
is able to detect time differences of ~10ms (that is 0,01 sec) as a delay!

Sorry for my lousy English... you know now what I mean?

---
Your English is fine; don't worry about it.

The human ear can detect arrival time differences far smaller than 10ms,
as I indicated in an earlier post. I was able to detect perceived
changes in the location of the source of an acoustic "click" in as
little as 2 inches, but even saying six inches (just in case...) that
comes out to less than 500 _micro_ seconds!

--
John Fields