Almarg,
Did you mean feed the same signal (mono) to each channel of a stereo amp? If so, you are correct that the output between the 2 hots will be essentially zero, showing only the channel imbalance....which should be inaudible.
If, however you feed a stereo amp a stereo signal THAN go from hot 2 hot, you will get an output. Back at the 'dawn' of multichannel....QS / SQ matrix and such, I would connect a pair of speakers normally as fronts, and another pair, from hot to hot.....put 'em in the back of the room and instant ambiance. No fine tuning possible, but as proof of principle, it worked. I think that was the principle behind the original 'dyanquad'....the speaker adaptor they sold.
Did you mean feed the same signal (mono) to each channel of a stereo amp? If so, you are correct that the output between the 2 hots will be essentially zero, showing only the channel imbalance....which should be inaudible.
If, however you feed a stereo amp a stereo signal THAN go from hot 2 hot, you will get an output. Back at the 'dawn' of multichannel....QS / SQ matrix and such, I would connect a pair of speakers normally as fronts, and another pair, from hot to hot.....put 'em in the back of the room and instant ambiance. No fine tuning possible, but as proof of principle, it worked. I think that was the principle behind the original 'dyanquad'....the speaker adaptor they sold.