I have to say that the whole phase inversion thing leaves a bit to be desired. Much good advice has already been posted. From my perspective, I have a Joule Electra LA-100 MkIII that inverts phase and a Hagerman Trumpet phonostage that has a polarity switch. I recently acquired a passive preamp that does not invert phase. My system is set-up so the digital front end runs through the passive and the analog front-end runs through the Joule. So I don't have to keep swapping the speaker leads back and forth, I just leave them wired + to + and - to -, using the polarity switch on the phonostage to reverse phase to compensate.
The funny thing about all this is that I really can't tell the difference. I have a few test discs, two CD and one LP. Using the voice phase tests swapping the speaker leads made no difference to my ears. However, swapping IC leads did. As for the Rives CD, they use a track with solo piano followed by solo bass. Again, I could not tell the differnece. Although Larri's point about the piano seems to make some sense now that I think back on it. I may have to revisit that test track.
The funny thing about all this is that I really can't tell the difference. I have a few test discs, two CD and one LP. Using the voice phase tests swapping the speaker leads made no difference to my ears. However, swapping IC leads did. As for the Rives CD, they use a track with solo piano followed by solo bass. Again, I could not tell the differnece. Although Larri's point about the piano seems to make some sense now that I think back on it. I may have to revisit that test track.