On 05/14/2011 05:31 PM, Phil Allison wrote:
"Tim Wescott"

"If the click seems to come from right inside your head - game over".

What more do you need? Phil's given you a test to see if the phasing is
correct, can you not figure it out, or what to do if the click seems to
come from your right or your left?


** If both ear phones work but are wired out of phase, the AA cell click
test produces a sound that seems to be originating outside the head on both
sides. Mono speech or music sounds much the same.

The effect is far MORE pronounced than with typical stereo speakers in a
room.

The OP demonstrates his a monumental ignorance of headphones, hi-fi sound,
usenet etiquette and common sense.

Only tangentially related, and mostly useless:

Amateur radio folks like building direct conversion receivers (i.e., mix
down to baseband). They're simple, hence little, and they work pretty
well. Their biggest problem is that they have no audio image rejection
at all -- listening with a 7040kHz oscillator, you'll hear a signal at
7040.5 just the same as one at 7039.5.

You can get around this by making a so-called "phasing" receiver
(basically an image-reject downconverter, but ham radio has its own
terminology), but then you're back to something complex.

If you build an I/Q downconverter, and amplify each channel to a
headphone channel, then apparently you get a spatial perception of the
tones -- upper side tones sound like they're coming from a different
point in space than lower side tones, and (presumably due to the phase
shift in the amplifiers, I don't know) high and low tones do as well.
It's claimed that this makes it easier to use for morse code reception.

I've always thought that was interesting, but haven't tried it.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html