Stewart Pinkerton wrote:
On 21 Oct 2003 22:48:38 GMT, chung wrote:

All Ears wrote:
"Bruce Abrams" wrote in message
...
snip

You just can't reproduce sounds from behind you with
speakers in front of you. It's impossible.

This is not entirely true, actually the ears works as a filter, so that
sounds comming from behind will have a dramatic drop in the 8 kHz area. This
means that if you cut the 8kHz area from a sound image, it will appear as
the sound is comming from behind.

KE

I don't think it's that simple. Let's say you play some bass notes on
speakers in front of you. There is no 8KHz in those bass notes. How can
the ear interpret those as coming from the behind?

How can it interpret them as coming from *any* location? Ever tried to
decide which phone in a modern office is ringing?

OK Stewart, I'll bite. How does one know if sound is from the back?

I have always thought that it is the difference in amplitude and phase
of the sounds arriving at the left and right ears that provide location
information. But obviously, if a sound is coming from behind you in the
middle, there may not be any difference in what each ear perceives.

On the other hand, I don't think it's as simple as a notch filter around
8 KHz. A telephone ringtone does not have much 8KHz component, yet
clearly I can tell if a phone is ringing behind me. When one of the many
phones rings, I think most of us will turn our heads to find a spot
where the sound is somewhat front-center of us, and then focus on the
ringing source. Well, most of the time at least. What if a 1KHz tone is
played. Can one tell if the tone comes from the back or front without
turning one's head?