Testing that speakers in phase?

**Eeyore** · May 5th 08, 01:09 AM posted to uk.rec.audio,uk.comp.homebuilt

GSV Three Minds in a Can wrote:

Bitstring , from the
wonderful person TheFug said
Terry Pinnell schreef:
Could someone remind me of the simple test involving placing 'left'
and 'right' speakers close together facing each other please? Am I
right in recalling that they are in correct 'phase' when the volume
sounds reduced/muffled? Or is it the reverse?
(I have some cable extensions to do on the speakers that came with
my
new PC, and both wires are identical, so I want to be sure I get it
right.)

use a Light Emitting Diode LED play music at low level, while
placing led over connections, LED can only light up at one way
connection position....

That makes the rash (especially with cheap speakers) assumption that the
speaker connections are hooked up to the internals the same way in both
cases. Much safer to actually test the sound output (or, as someone
said, to see which way the cone moves with a DC source).

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

Graham

**GSV Three Minds in a Can** · May 5th 08, 08:18 PM posted to uk.rec.audio,uk.comp.homebuilt

Bitstring , from the wonderful person
Eeyore said

GSV Three Minds in a Can wrote:

Bitstring , from the
wonderful person TheFug said
Terry Pinnell schreef:
Could someone remind me of the simple test involving placing 'left'
and 'right' speakers close together facing each other please? Am I
right in recalling that they are in correct 'phase' when the volume
sounds reduced/muffled? Or is it the reverse?
(I have some cable extensions to do on the speakers that came with
my
new PC, and both wires are identical, so I want to be sure I get it
right.)

use a Light Emitting Diode LED play music at low level, while
placing led over connections, LED can only light up at one way
connection position....

That makes the rash (especially with cheap speakers) assumption that the
speaker connections are hooked up to the internals the same way in both
cases. Much safer to actually test the sound output (or, as someone
said, to see which way the cone moves with a DC source).

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

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

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

**Eeyore** · May 5th 08, 08:48 PM posted to uk.rec.audio,uk.comp.homebuilt

GSV Three Minds in a Can wrote:

Eeyore said
GSV Three Minds in a Can wrote:
TheFug said
Terry Pinnell schreef:
Could someone remind me of the simple test involving placing 'left'
and 'right' speakers close together facing each other please? Am I
right in recalling that they are in correct 'phase' when the volume
sounds reduced/muffled? Or is it the reverse?
(I have some cable extensions to do on the speakers that came with
my new PC, and both wires are identical, so I want to be sure I get it
right.)

use a Light Emitting Diode LED play music at low level, while
placing led over connections, LED can only light up at one way
connection position....

That makes the rash (especially with cheap speakers) assumption that the
speaker connections are hooked up to the internals the same way in both
cases. Much safer to actually test the sound output (or, as someone
said, to see which way the cone moves with a DC source).

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

**GSV Three Minds in a Can** · May 5th 08, 09:23 PM posted to uk.rec.audio,uk.comp.homebuilt

Bitstring , from the wonderful person
Eeyore said

GSV Three Minds in a Can wrote:

Eeyore said
GSV Three Minds in a Can wrote:
TheFug said
Terry Pinnell schreef:
Could someone remind me of the simple test involving placing 'left'
and 'right' speakers close together facing each other please? Am I
right in recalling that they are in correct 'phase' when the volume
sounds reduced/muffled? Or is it the reverse?
(I have some cable extensions to do on the speakers that came with
my new PC, and both wires are identical, so I want to be sure I get it
right.)

use a Light Emitting Diode LED play music at low level, while
placing led over connections, LED can only light up at one way
connection position....

That makes the rash (especially with cheap speakers) assumption that the
speaker connections are hooked up to the internals the same way in both
cases. Much safer to actually test the sound output (or, as someone
said, to see which way the cone moves with a DC source).

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

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

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

**David Looser** · May 5th 08, 09:31 PM posted to uk.rec.audio,uk.comp.homebuilt

"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.

**GSV Three Minds in a Can** · May 5th 08, 10:43 PM posted to uk.rec.audio,uk.comp.homebuilt

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** · May 6th 08, 06:27 AM posted to uk.rec.audio,uk.comp.homebuilt

"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.

**nobody >** · May 5th 08, 10:58 PM posted to uk.rec.audio,uk.comp.homebuilt

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.

**David Looser** · May 6th 08, 06:21 AM posted to uk.rec.audio,uk.comp.homebuilt

"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.

**Eeyore** · May 6th 08, 07:10 AM posted to uk.rec.audio,uk.comp.homebuilt

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