Has Anyone Ever Run TWO Identical Pairs of Speakers ?

I have 2 pairs of HPM-900's  identical in every way, even the re-capped x-overs are the same. So I tried the side by side method, not a very good outcome, but when I tried the vertical stack I was impressed, kinda like 2 big PA stacks at a concert, sort of a wall of sound if you will.

Actually, ran 3 pairs of inexpensive Pioneer bookshelves...hung in my shop for something to drown out the saws, routers, sanders.  'Low rent concert stacks'....vertical, natch...

An improvement on what they were, until the guys blew one of them in a fit of enthusiasm.

Going to knock them down to 2 pairs and add a CV I’ve been gifted with as a ersatz sub. It’s about what it’s worth doing with, anyway. ;)

Pretty much the same for the ’neers....*L*

Rude experiments in cheap audio; not ’phile, just tunes.

Oh, Sony receiver and 5 CD changer.  An old SAE 2 band paraEQ to smooth it out a bit.  Plug one's cell into it, not too bad in a 40x24 steel building with 13' ceiling....

I have two pairs of Magnepan MG 1.7i speakers. Since they are about 4 ohms I hooked these up in series to make an easier load for the amp, The room is about 20'x27'. Side by side on the narrow end of the room sounded about the same as one pair hooked up in the way the manufacturer suggests. I moved the second pair about one-third of the way out from the original position facing in the same orientation as the original pair. The system sounds bigger. My wife agrees. I also have two Velodyne 12R BG subs in the system to handle the bottom octave. The subs are connected in two-channel mode. The Berning EA 230 sounds better at low volume than the McIntosh MC 2105. I am currently using the 2105 because it has more power. I do not listen at very high volumes. The real piano in the room sounds very similar to the pianos on many recordings if they are well recorded even with one pair of Magnepans.

I've played with multiple drivers a lot over the years and found single drivers for each frequency range, sound the clearest. Get them as close together as possible, in vertical alignment. As mijostyn pointed out, multiple tweeters smear and fracture the sound (not his words) mine. This is true for the midrange as well and also for the bass above say about 100Hz. or so. I modified my system to reduce the number of drivers to one per frequency range and found a significant improvement in clarity and detail without changing anything else. This was true whether running the drivers in parallel, series or a series-parallel combination. While high efficiency is important and desired for hi-fi audio, multiple drivers for the same frequency range is NOT the way to go. For those using multiple drivers to cover the same frequency range using ANY speaker manufacturers drivers, please try a single driver for the same frequency range. You will see a noticeable improvement in clarity. Use the same source material, preamp and power amp or amps for this test. For me, I use 3 stereo amps in a 3-way, 2-speaker stereo configuration. I use an analog active crossover at the amp inputs and no crossover, only straight copper wire from the drivers to the individual amplifier outputs. I have A/B'd the configuration of single drivers versus multiple drivers of the same manufacture, the results are conclusive for me. I will never go back to multiple drivers for the same frequency range for listening levels up to about 105dB SPL. I invite all on this forum to try it, and to make it more convincing, use an SPL meter. Best wishes in your pursuit of excellence!