Unusual Old School Way of Wiring Speakers

@sworksone - Yes, indeed.

Whew!!! I'm glad I'm not going crazy and making stuff up in my head...about this anyway. Thanks everyone, this is the info I was looking for... Just for the fun of it, I'm going to play with this in my office system.

What the Dynaquad box does is create a left minus right signal (the opposite of a left plus right mono one, as used for the center speaker in 3-channel stereo---somewhat popular in the 1950’s, and of course in home theater for the dialog channel). That signal is then sent to a separate amplifier powering a pair of rear loudspeakers.

The box includes a volume pot on it’s faceplate, necessary to allow balancing the rear loudspeakers with the front pair. The box receives it’s signal from the power amp---a high-level source, of course. In the 1980’s Acoustic Research introduced a box which produced the same left minus right signal, but did so at line level, taking it’s signal from the pre-amp. It was intended to be a cheap way to create a home theater-type surround sound effect, but can also be used to create "spaciousness" from 2-channel sources. That box (sorry, I don’t recall it’s name/model number) and the Dynaquad box can be found for not much dough.

That pair of rear channel speakers (it has to be a pair) reproduces and reveals any out-of-phase information/sound sometimes found in stereo recordings, a random phenomenon. Out-of-phase information is not-uncommon in recordings made in large venues: concert halls, cathedrals, etc. It is less common in close-mic’d studio recordings. A cheap, fun way to create an "immersive" sound field!

That’s the old DynaQuad hookup devised by Dynaco to be used for a rear pair of speakers to add ambience. Dynaco sold an adapter box for this purpose. I recommend searching online (eBay, etc) and buying the DynaQuad box to experiment with.

Is this what you’re looking for?

I'm not having any luck finding anything about it, but I thought I read about connecting a rear speaker to one of the outputs (i.e. lefts or rights) from the main speakers with the result being a bit of a phantom channel the added some depth.  Does this sound familiar?

It generally requires having a special added driver in each speaker.  It was developed by Bob Carver and marketed, to this day, by Polk.  See

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If I remember correctly, Fried produced a version of their model C satellite speaker (C-6?) with a special crossover and dual voice coil mid bass drivers. There was a way to connect the two speakers so that the second voice coil was out of phase and was supposed to enhance the spatial presentation of the speakers. It was specific to those models that had the specially designed crossover though. 

I believe VanL speaker works out of Chicago had a speaker that did something similar. I don't remember the model though.

Sorry, I should have written it more clearly, this is in a two channel stereo system.

A center channel?