[Mike Rivers]

On May 29, 2:29 pm, Mark wrote:

The quick FFT test proves that there is no change except polarity in
the ELECTRICAL signal fed to the speakers. It says nothing about the
sound signal comming out of the speakers. I'll need to set up a mic
for that test and get back to you.

If your speakers don't work like speakers, all bets are off. The
assumption is that the speaker is linear at least to the extent that
one polarity makes the cone move outward from the center position and
the opposite polarity makes it move inward.

Becasue I obtained different results by moving my head. One time the
first polarity appeared to have more bass, the next time the second
polarity appeared to have more bass.

Well then don't move your head. Or better yet, disconnect one speaker.
When you add in room effects, you disturb the experiment. This is not
about stereo, it's about polarity and speaker cone motion.

Deny it if you will, but it's real.