Reversing Polarity -- Voodoo or Easy Tweak?

If you reverse the leads on only one speaker, you will be out of phase, and your imaging will be wrong. This can be easily checked with any available test disc. It's pretty easy to hear. A single vocal will not have a centered image, but will instead be split across the soundstage.

Absolute phase is something different. To reverse absolute phase, you reverse the +/- leads on both speakers. Absolute phase is more difficult to hear, but it's easy to experiment. BTW, you can reverse leads at the amp instead of the speakers with the same end result.

Absolute phase, and phase (what Eldartford calls "relative" phase) are two different things, thus the difference in approaches to wiring the speakers to correct the problem.

Well, I thought I understood this topic, but I'm as confused as I've ever been.

Herman, your explanation makes sense, however I want to understand the effect of polarity, and the solution.

I own Stereophile's Test CD3, on which track 2 is titled "Stereo Channel Phasing". The description, and effect appears to be what you're referring to as polarity. Quoting from the Stereophile Test CD3 text:

What you should hear: In a conventional stereo system, a centrally placed listener should hear the image of the in-phase noise occupying a very narrow space centered between the loudspeakers, If the sound "splashes" to the sides at some frequencies, or the image is broadened at all frequencies, then there is something suspect in your system-most probably a loudspeaker or room-acoustic problem. The image of the out of phase noise should not be centered; in fact, it should generally be very hard for you to point to where it's coming from. With some loudspeakers, however, the out-of-phase noise might appear to come from a point to the outside edge of either the left or right loudspeaker. If you don't hear these clear distinctions between in and out of phase noise, or if you hear them reversed, try inverting the connection to one of your speakers.

The way I understand this is simply...from amp to speaker, connect plus to plus and minus to minus on both speakers. Connecting plus to minus on only one speaker usually results in the out of phase (polarity?) phenomenon mentioned in the quote from Stereophile.

Do I have this right? Is Stereophile referring to polarity when they speak of phase?

Cripes, my head is spinning...maybe it's out of absolute phase.

Cwlondon wrote:

what happens?
and why do some recommend?

changing the polarity on BOTH speakers.

Although the "polarity" in this case changes, it does so on both speakers, the polarity remains consistent so the signal remains "in phase".

This is reversing Absolute Polarity (I mistakenly referred to this as Absolute Phase in an earlier post). In my experience, when the signal is in correct Absolute Polarity, the sound is somewhat fuller, and more complete. The stereo image will remain focused and centered just as when the polarity is maintained plus to plus, and minus to minus.

It's interesting to note that one manufacturer of equipment I own refers to this as Absolute Polarity, and another manufacturer refers to this as Absolute Phase. No wonder there's confusion!

Regarding your statement about the necessity of a test disc to hear correct phase, I don't believe the use of one makes the listener a less-than-self-respecting audiophile any more than the use of a tape measure makes a less-than-self-respecting carpenter. Frankly, for someone new to the hobby, which we all were at one time, a test disc can be an extremely useful tool. Futhermore, the Phase track on the Stereophile Test CD is a quick and easy way to double check for correct polarity (phase) without uncertainty or guesswork.

Am I the only one who thinks this thread reads like Abbott & Costello's "Who's On First"?

What's on second. Who's on first, and Polarity's in the bullpen.

Question why would any one record music reversing the signal polarity deliberately?

Perhaps to give their music a distinctive and uniquely different sound.

Here's an idea. Why not write to Dave Grusin and ask him?

Jea48, no, I didn't wink. Why? I was serious. Write him and ask him...unless he's dead, and I didn't know it?

Perhaps one issue with this recording is that it was cut direct-to-disc. Maybe doing so eliminated one link in the signal chain that would have otherwise corrected the polarity? Just guessing here...

Jea48, Bingo! That's what I thought...adding another amp into the signal chain would have degraded the sound.

Nice research. Now you can sleep at night.