Does this work

[Pelliott321]

https://www.psaudio.com/pauls-posts/4-channel-audio/

[SoundMods]

https://www.psaudio.com/pauls-posts/4-channel-audio/

Yes -- in a way. Hafler sold a box that would route the ambient information on a recording to rear speakers. It was not true four channel but it would create an open acoustic within the listening area. Carver did something different with his Carver Hologram Generator that would play games with the front speakers.

[Pelliott321]

thanks walt

[mix4fix]

In late 80s/early 90s, there was a car audio full range speaker box that used "tri-mode", which I think was just using a single dual terminal woofer with one terminal going to the left box input terminals (and the horn/tweeter/midrange/etc) and the the other to the right. Mono lows/stereo highs.

There was also a tri-mode passive crossover that accomplished the same thing outside of a box.

[mix4fix]

Wait. Back speakers out of phase?

[SoundMods]

thanks walt

You're welcome! I played with both in the far distant past.

[pboser]

It’s not out of phase. It’s a difference signal- left minus right.

[mix4fix]

Will this work on any amplifier? Do the speaker pairs have to be the same or similar?