Reversing Polarity -- Voodoo or Easy Tweak?

The correct term when talking about wiring speakers is polarity as stated in the original question, not phase.

Phase has to do with time, polarity has to do with whether a signal is going positive or negative. If a speaker is wired with the wrong polarity it will be going out when it should be going in, and vice versa. I have friend who claims he can tell when it is reversed because a vocalist will sound like they are gulping air instead of exhaling.

When 2 signals are out of phase it means that one or the other has been shifted in time, it occurs earlier or later in time than originaly produced. One example is a crossover network. They not only attenuate the signals outside their passband, they also phase shift them so they occur at a different time relative to those in the passband.

The fact that many manufacturers use the terms interchangeably adds to the confusion, just as Eldartford did in his post. In the first part where he is talking about wiring the speakers the correct term is polarity. In the second when he talks about the Buffy Sainte-Marie recording the correct term is phase. This deliberate phase shifting is the same thing Hendrix did to get that swirling effect with some of his recordings.

Herman

Excellent post!

Tvad

At the risk of oversimplifying things here:

If ONE speaker has + and - (it's polarity) reversed, then the system will be "out of phase".

And no offense , but no self respecting audiophile should need a test disc to hear this -- it creates a weird, vague image, and to my ears at least, a slightly disorienting, almost uncomfortable to the inner ear wandering sound.

When I sold hi fi during college, the owner of the store thought it would be amusing to demonstrate my lack of experience by asking my opinion on a system where he had wired the Acoustat speakers "out of phase". It took me about 15 seconds to hear this.

During the recording process, however, certain things might be recording about of phase to create weird imaging effects. In addition to Jimi Hendrix, I think Roger Waters Amused to Death is known for this type of demo.

My original question of course was

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".

I think I am using these terms correctly now?

Cwlondon, I understood you in your first post. Few are stupid enough to wire one speaker out of phase with the other. Absolute polarity is a different matter. I wish I had an easy way to have switchable polarity, so that I had a choice, but I don't have. Even cheap digital players used to have this, but no longer. I am not about to change speaker leads for each cd or record.

In the past, on perhaps 10 percent of my records changing the absolute polarity made a great difference. On about 30 percent it made no difference.

The Grusin LP was recorded with the absolute polarity reversed. Shefield realized it after the fact and this is the reason for noting it on the cover. About half of the LPs and CDs have the polarity reversed. Some of the offenders are Mercury Living Presence, RCA Living Stereo, Capitol, MCA, Decca/London, DG and Warner. When your ear is trained to hear this, it will take about 3 second to pick up on it. I don't do vinyl anymore so it's easy for me to correct with the polarity switch on my Theta DAC. Then I mark the CD insert with a green (correct)or red (180 degrees)sharpie. A polarity switch on the preamp's remote would be even easier. Listen to a recording of Nat King Cole on Capitol both ways. There is a huge difference in these recordings and it's easy to hear. If you can't hear the difference, well...