"Eeyore" wrote in message
...


GSV Three Minds in a Can wrote:


Audio is AC you blithering loonies. No way can an LED inducate
polarity/phase.

It can if you play REALLY low frequency music. 8.

NO

Oh I dunno. If you use a very low frequency tone (NOT music), say 10Hz, and
connect an LED across each speaker (not forgetting a suitable series
resistor to avoid the risk of damaging the amplifier), and being absolutely
sure that both LEDs are connected the same way round (not always easy) and
by placing the two LEDs next to each other you might, just might, be able to
see if they are flikering in phase, or out of phase.

As a way of determining speaker phase it has the problems of being difficult
and cumbersome to do and uncertain in it's outcome, but it's not utterly
impossible. But since determining speaker phase is so easy to do using ones
ears there seems little point to the LED method, though it might be of use
to the stone deaf.

:-)

David.