"Meat Plow" wrote:
On Wed, 02 Jan 2008 17:11:29 +0000, Arfa Daily wrote:

wrote
[...]
Over the years I've read a number of different views on the effect of
wiring speakers with reversed polarity. I've heard everything from "it
won't really matter if the speakers are both wired the same way" to
"the sound won't be as good because the speaker cone will pull inward
instead of being pushed out".


It wouldn't be hard to fix, but should I bother correcting the
polarity?

William

I've never known it to matter, as long as they are both wired the same way
round, as you say. Reverse wiring just one will result in a lack of bass and
a 'woolly' stereo image, as I'm sure you are aware. If you think about it,
any waveform driving them will have a pretty symmetrical count of positive
and negative half cycles of largely similar amplitude, so there is no real
reason why the speaker moving back, at a time when the diaphragm in the
microphone that made the original recording was moving forward, should have
any effect. The theory also assumes that the phase relationship was
maintained throughout the entire recording process, and that there is no
inversion taking place in amplifier stages in your player, that isn't
reversed again, by the time the signal reaches the output terminals ...

Arfa

It would matter for impulses from the waveform say as in a drum beat?
Wouldn't the beat of a kick drum cause the speaker cone to move inward if
the polarity is reversed? This certainly wouldn't be suitable for a sound
reinforcement system.

Basically (and I have some experience with audio and hi-fi, including an
electroacoustics degree - but I am NOT an "expert"), I agree with Arfa that
for MOST practical purposes, as long as both speakers are connected with
the same polarity, then it'll be fine and you won't be able to distinguish
one polarity from the other.

If one speaker is wired in antiphase with the other, you'll lose bass to
an extent that depends on room geometry and speaker positioning - but
whatever happens, it won't be good.

There has indeed been debate about whether people are sensitive to
"absolute phase"; and I remember reading about higher-end DAC units for
CDs that included a switch to flip phase on both channels. ISTR, an d
I may be wrong, that back in the late 80s when I had a part-time job
at a hi-fi shop, there was a Musical Fidelity outboard DAC unit that
featured such a switch - but it was 20 years ago, so don't quote me.

Personally I don't believe that people are sensitive to absolute phase, and
anyone who claims they are needs to submit to a double-blind test, and
maybe if they pass, go and have a word with James Randi, who while
AFAIK he isn't offering a prize for absolute phase YET, may be interested
in handing out a financial prize if they can repeat the souble-blind
performance repeatably. He offers a prize to those claiming to be able to
distinguish between interconnect cables (providing both sets are reasonably
well-executed and one pair isn't made of wet string, for example!).

As Meat Plow suggests, there COULD be an issue with high cone excursions,
where on a bass kick, or similar, the cone former may hit the endstop
on the way IN (away from the listener) with the speaker wired one way
round, but not with it wired the other way round. However, that's a
completely separate consideration unrelated to human sensitivity to
"absolute phase". You just hear a nasty knocking sound when it happens and
risk damaging your bass unit. If you're driving them that hard though, you
may encounter problems regardless of polarity.

Summary: Make sure both speakers are wired the same way round. That done,
forget worrying about it. Unless you're maybe doing an acoustics PhD.


Martin
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M.A.Poyser Tel.: 07967 110890
Manchester, U.K. http://www.livejournal.com/userinfo.bml?user=fleetie