Preamp inverts phase question:

Easy test. Play a dozen LPs, CDs, and/or reel-to-reel tapes. After you listen each one, switch the speaker connections left-to-right (+ to -, red to black, whatever) on both speakers. Play again. Do you hear any difference in any of them? If not, count your blessings and forget the whole thing (because your speakers do not reveal polarity* differences). If you do hear a difference, then decide if it's important enough for you to keep switching speaker cables or invest in a polarity-switching preamp like the Aesthetix Calypso.

* I think of this as polarity switching rather than phase switching, but it's probably best not to get into that.

On typical poorly recorded, heavily multi-miked, heavily processed material, absolute phase (or polarity, as Dopogue points out) will clearly make either no difference or a random difference. On string instruments, and many other instruments as well, I'd imagine it would also make no discernable difference, as Ghstudio points out.

However, on a high-quality audiophile caliber recording, that is done using just two or three microphones, that is minimally processed, and especially one that contains sharp percussive sounds, you can find many comments by equipment reviewers and others indicating that there will be subtle but audible degradation if polarity is inverted.

As Dopogue alluded to, some preamps even provide for on-the-fly polarity switching via remote control.

My own philosophy has been that it's easy enough to keep the system phase correct (unless, as I mentioned previously, the source components differ from one another), so I just do it and don't worry about whether or not having it wrong would make a difference.

Regards,
-- Al

Adampeter,
Here is some reading material that backs up what Al has been saying.

Stan Ricker

Absolute polarity, How important?
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I'm sorry, but phase really does matter and is very important. The difference is very apparent to me when using a phase inverting phono preamp. Why just assume that some recordings may be phase inverted, so it doesn't matter. You should configure your system to replay music properly, and that means switching the cables at the speakers to compensate for the preamp being phase inverting. Let the recordings that are "wrong" be wrong and let the ones that are phase correct play back properly. It is silly to set up the system "wrong" because phase might not matter. Set it up properly and let the chips fall where they may.

It only matters, Hifiharv, if it's audible. I could never hear polarity differences ("normal" vs "inverted") until I got my current speakers (Gallo Reference 3) which the manufacturer says "are very polarity sensitive." Most of my friends' systems are not polarity-coherent and it's pointless for them to mess with it if they can't hear it. Dave