Phase Inversion


recently read about a cary slp98 pre amp as well as a few others that are phase inverting. also read that this can be reversed by changing the polarity of the speaker wires. my question, why do manufacturers do this? does it make an audible difference? why reverse it? i also have read about cd's that are recorded phase reversed. what is the point of all this. thanks alot.

aloha keith
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The problem is how many times is the polarity reversed during the entire process starting with the recording?
Most likely a number of times. If that is the case I dont think it makes much difference.
There is an interesting book called "The Wood Effect" (sorry, but I've forgotten the author). This is a rather detailed book that cites many studies and tech papers (with lots of footnotes) regarding 180 degree phase inversion. According to this book, as well as my own observations, by switching phase (reversing BOTH speaker terminal wire connections or using a phase inversion switch, if available, on your preamp), you will get a noticeable change in sound reproduction on most source material! These changes include: wider soundstage, and better soundstage pinpointing of vocals and instruments.
FAT PARROT,

are you saying that inverting phase (polarity) sounds better? i will try this out.

aloha keith
I thought Clark Johnson wrote the Wood Effect.

Most recording engineers are unconcerned with polarity. As a result roughly half of all recordings are incorrect. You will want a switch to do the job- getting up to change the speaker cables can get to be rather a pain :)

If you are listening to multi-tracked recordings it may make no difference, as tracks get inverted going through effects loops and the like, so its one jumble for another. But if it is a pure recording (2 or 3 mic true stereo) the difference can be quite notable.