Does anyone play two pairs of speakers at the same time?

Running 2 pairs of dissimilar speakers at the same time is such a bad idea, in a stereo system. Especially in the high frequencies.

Not sure if the OP is talking about stacking them, or playing them on 4 different walls, but either way, not good.

People, comb filtering is a thing. The frequency response would be completely unpredictable, there is no way to know if some frequencies are going to increase or decrease due to frequencies from one speaker’s dips or rises in frequency response meeting the other speaker’s dips and rises.

Then there are difference in lobing caused by different drivers and different crossovers. I am sure that imaging and soundstage would be close to nonexistent.

Check out the following video by speaker design wiz, Danny Richie. He explains why 2 tweeters on the same baffle is a bad idea, but a lot of what he says can be translated to multiple speakers of different designs also. Unless special circumstances are taken into consideration, like line arrays, for example.

https://www.youtube.com/watch?v=MGSfaKWcetQ

I would guess that any result that would sound ’good’ would be the result of certain frequencies, like maybe the presence region (4-6 K), being increased or decreased, depending on if the listener like bright or rolled off sound, or increase in bass response, etc.

Back in the early to mid 70's, some dealers would stack two pair  of EPI 100"s with excellent results. Often besting the stacked Advent pairing. Although the smaller EPI woofers didn't have the bass extension of the Advents.

Why is it people like a blended whiskey ? Or a V8 in a Chevy Monza or a Maverick? Life is complex, the grail elusive....

now a Klipsch and Maggie marriage must sound like a tortured Labradoodle on speed...

Yeah @simonmoon, the Danny Richie Tech Talk Tuesday videos are fantastic. Tekton owners might want to not watch them, though ;-) .

 I have attended many live classical musician and jazz concerts. There are many of the same instruments with different manufactures playing together at the same time creating beautiful music. I always thought a speaker for each instrument playing only that instrument in it's exact spot would be an interesting experiment. I have owned many pairs of speakers and amplifiers, I have also played up to 7 pairs of various speakers set to the same volume using a spl meter at the same time. Most combinations don't sound better than the single pairs, just different. However some pairs have sounded decidedly better in the full frequency range and on various music sources.  It's a hobby and a blast messing around. I have also been doing this for 50 years and still enjoying myself. Have fun, but remember live is best and at home it's all about the music. Stretch your ears.