Odd way of wiring three speakers to an amp

I have a very dusty memory of a diagram to wire up 3 speakers to an amp for home use that gave an interesting effect. From what I remember it was big in the 70s. I can't rememeber the diagram. I thought it may be like this:



But I think I have the third one wrong.

Anyone remember this and also what the config is called?

Many thanks

tendril

If you connect the third speaker as you would in bridge mode, across the left and right positive channels, the speaker will receive the difference between left and right. The earliest surround sound encoding worked roughly on that principle so if you put the third speaker behind you while listening to suitably encoded tracks you'll get a basic surround sound effect. Works well on Star Trek - TNG actually, you get the sound of the ship (low rumble/hum type sound) coming from the rear speaker.

chaudio wrote: If you connect the third speaker as you would in bridge mode, across the left and right positive channels, the speaker will receive the difference between left and right. The earliest surround sound encoding worked roughly on that principle so if you put the third speaker behind you while listening to suitably encoded tracks you'll get a basic surround sound effect. Works well on Star Trek - TNG actually, you get the sound of the ship (low rumble/hum type sound) coming from the rear speaker.

so, like this then:

Yeah. Only do it on amps which don't mind low impedance loads. ie. don't do it on a hi-fi amp that says 8 Ohms only. Although at low volumes, most things will cope with it.

Thank you very much

Seen this in car audio, often wondered. Nice thread. Ta

I'd forgotten all about this one. It was refered to as the 3rd channel, and definately talked about in the old Hi Fi mags.

Any suggestions about whether the centre / rear speaker should be voiced the same as the mains - is the effect full range or bass only? If full range, I have some nice Ariston cylindrical speakers which just might do the biz on my Quad 405 but I shall try at low levels first to see how things work. I also forgot about this - first read about it in a magazine called Studio Sound I used to get in the seventies and early eighties!