"out of phase" 3rd speaker

[azrockitman]

Ok, we were young   

Back in the '60's, my cousin read about hooking up a third speaker "out of phase" to create a unique effect.  You would run a single wire off the L terminal of one channel and a single wire off the R terminal of the other channel, to a third speaker;  those two wires would be connected traditionally to the L/R speaker inputs on the single speaker.  The L and R traditional speakers would be active and wired correctly.  If I recall, the effect was kind of like a reverb...it added a dimension to the sound that was quite unique. I suspect it would not sound as good today as we thought it sounded back then....

I have no idea what that was actually accomplishing.  You would basically end up with half of each signal being wired into one speaker creating kind of a bastard mono signal...?!?

Anyone ever heard of this weird practice?

[4krow]

  Yup, I remember that. I recall that the L+R center speaker was a lot less loud.

[4krow]

 Maybe I should clarify. The center speaker was connected to the positive leg of the Left AND Right channels.

[Grainger49]

That was David Haffler's DynaQuad.  You could put two rear speakers, in series and out of phase across the left and right terminals of your amp.  They gave the output (L-R) + (R-L), the "difference" channel.  You could use an 8 ohm L-Pad as a trimmer to match the speaker levels. 

As soon as I saw it I started giving it to customers. 

[2wo]

I know that "center Chanel" outputs were on some 60's gear. I think Klipsch used to advocate it as well...John