"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.

"GSV Three Minds in a Can" wrote in message
...

Sure it can. You just need something around 0.1hz.

You won't get 0.1Hz through an audio amplifier!

David.

Bitstring , from the wonderful
person David Looser said
"GSV Three Minds in a Can" wrote in message
...

Sure it can. You just need something around 0.1hz.

You won't get 0.1Hz through an audio amplifier!

Who was talking about using an audio amp? I was musing between a
frequency generator, and maybe just a battery and switch. I did say it
was a dumb idea though, since you can only test at the terminals on the
back on the speaker (unless you knock it to pieces), and with cheap
speakers they are just as likely to be mis-wired inside.

--
GSV Three Minds in a Can
11,517 Km walked. 2,259 Km PROWs surveyed. 40.9% complete.

David Looser wrote:
"GSV Three Minds in a Can" wrote in message
...
Sure it can. You just need something around 0.1hz.

You won't get 0.1Hz through an audio amplifier!

David.



Some can, a Crown DC300 comes to mind immediately.

In article ,
David Looser wrote:
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.

LEDs can fail with reverse polarity.

--
*Work like you don't need the money. Love like you've never been hurt.

Dave Plowman London SW
To e-mail, change noise into sound.

"nobody " wrote in message
m...
David Looser wrote:
"GSV Three Minds in a Can" wrote in message
...
Sure it can. You just need something around 0.1hz.

You won't get 0.1Hz through an audio amplifier!

David.



Some can, a Crown DC300 comes to mind immediately.

Only if you bypass the input coupling capacitor. And then it becomes an
industrial amp, not an audio one.

David.

"Dave Plowman (News)" wrote in message
...
In article ,
David Looser wrote:
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.

LEDs can fail with reverse polarity.

Indeed, so as well as the series resistor you should really use a shunt
protection diode as well!

David.

"GSV Three Minds in a Can" wrote in message
...
Bitstring , from the wonderful person
David Looser said
"GSV Three Minds in a Can" wrote in message
...

Sure it can. You just need something around 0.1hz.

You won't get 0.1Hz through an audio amplifier!

Who was talking about using an audio amp?

That's what this thread was about. We were talking about speaker phase, and
speakers are only ever driven by audio amplifiers!

I was musing between a frequency generator, and maybe just a battery and
switch. I did say it was a dumb idea though, since you can only test at
the terminals on the back on the speaker (unless you knock it to pieces),
and with cheap speakers they are just as likely to be mis-wired inside.

Well it IS a dumb idea, a particularly dumb idea, but not for that reason.
I've never come across mis-wired speakers and frankly I don't believe that
any factory-made speakers, even the very cheapest, would have the two
speakers of a stereo pair wired differently.

David.

David Looser wrote:

"GSV Three Minds in a Can" wrote

Sure it can. You just need something around 0.1hz.

You won't get 0.1Hz through an audio amplifier!

You won't get 0.1Hz through a speaker either !

Graham

On Tue, 06 May 2008 08:10:28 +0100, Eeyore
wrote:



David Looser wrote:

"GSV Three Minds in a Can" wrote

Sure it can. You just need something around 0.1hz.

You won't get 0.1Hz through an audio amplifier!

You won't get 0.1Hz through a speaker either !

Graham

Fan-based subwoofers will do it.

d
--
Pearce Consulting
http://www.pearce.uk.com