phase correction for records?

Well, Jenny, you gain nothing by switching only one speaker cable. This
should merely produce out-of-phase sonics with a "diffuse and
directionless quality," to quote what the guy says on an ancient Shure
test record. I can't account for what you're hearing by switching both speaker
cables. It should have an effect, yes -- assuming your speakers are polarity-
coherent -- but nothing as dramatic as what you're reporting.

When you say you picked out a record that didn't have any phase problems,
you should bear in mind that records were originally recorded in
"normal" (absolute, if everything is hooked up properly) polarity,
in "inverted" polarity, in mixed polarity, or in some combination of
the above. Engineers either didn't care or figured the listener wouldn't hear
the difference or wouldn't care either.

Some records were recorded with a vocalist, say, in different polarity from
everything else. So depending on how you reproduce it, you can bring the
vocalist out front, or push him/her back into the mix. This is a maddening,
complex subject. One of my audiobuddies simply refuses to play the game
(he can hear the difference but ignores it). Frankly, If I were you, I'd follow
his lead :-)

You can check to see if it's a phase (polarity) issue or not by playing one of your
problem records and then reversing the speaker cables* to BOTH speakers (at
the speaker end). See if you can hear a difference. This will also tell you
whether the speakers are polarity-coherent. Count your blessings if they're
not, because unless you want to go through the bother of constant speaker
cable switching -- and if you're really sensitive to the effect -- you'll have to
get a preamp with a polarity switch. I don't know of any integrateds that have
such a switch, but there may be some. Good luck, Dave.

* I assume you know to power down before doing this.

That's odd, Raul. I have a friend with those giant Souindlabs AND a preamp with a polarity switch and he disabled the switch because he was never able to hear the slightest difference with it in either position.