what I mean is the use of the positve speaker output from the left channel output from a 2 channel stereo amp "ST70 in my case" and the negative on the right channel output while at the same time using a stereo pair of your speakers just like normal with a third hooked up this way.
It's been written about for helping car audio getting better imaging or for very wide rooms to help center the voice. "I believe it's where dolby surround got it's start" It's an old trick that's been around for awhile.
IF YOUR RUNNING AN AMP WHERE YOU MAY BE WORRIED ABOUT DROPPING THE SPERAKER IMPEADENCE TO LOW I WOULD NOT SUGGEST TRYING THIS.
Well I came to a conclusion for a new use for this trick that was broght up by my current work area system. The system uses a pair of bookshelves that could use some extra bass and I have plenty of drivers and cabinets not to mention a plethera of xover parts. So I put a 10" bass driver in a pretty big cabinet used an old passive sub filter "coil and cap" hooked it up the way I described above shoved it under the desk and whala I have great bass now!
Pretty cool setup, I was preparred to use a pot on the bass driver and rework the passive network if need be, but I'll be darned if it's not just right ,HUMM!
It thought there was one method which uses an actual network where you can dial in the volume of the center channel. Paul Klipsch did that with Klipschorns in far away corners and a center speaker (long before multi-channel receivers).