On 21 Oct 2003 20:18:37 GMT, Bruce Abrams
wrote:

"All Ears" wrote in message
...
"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.

That's not true. Your logic is faulty. You just effectively said that
since the sky is blue, anything that is blue must be the sky. Just because
the ear filters 8 kHz, sounds from the front that are cut at 8 kHz will not
automatically be located to the rear. There are directional clues that will
be missing. You just can't make a sound produced in front of a listener
sound like it's coming from behind the listener.

That's not true. Your logic is faulty. There are no 'directional
clues' in a direct front to direct rear traverse that don't involve
manipulation of the HRTF. Indeed, aside from transients, we generally
have great difficulty in distinguishing a sound directly in front from
one directly behind, *unless* it has significant HF content. Those
designing warning sirens for emergency service vehicles are well aware
of this - as is anyone who has ever tried to find their mobile phone
when it rings!
--

Stewart Pinkerton | Music is Art - Audio is Engineering