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

Focal speakers BE tweeters are typically 27mm (1.125"), like Dynaudio's esotar which is also 1.1". It's a little more directional than a typical 25mm tweeter, which generally leads to a less "airy" sound since you have less reflections.

At one time I ran a pseudo quadraphonic setup with four speakers. The speakers are wired to simulate quad by wiring them to utilize out of phase information. The details are probably available on line somewhere. It’s pretty cool. I also ran four speakers with the digital time delay unit I had for a while.

jamnov, congratulations on the exploration! It is terrific fun to explore/experiment with systems! You are doing a "stacked" speaker system variant, and with same brand speakers I'm sure it does sound very good. You have put many of the variables in your favor to have a good outcome.

Pretty amazing, eh, when you work from a consistent amplification on such setups. A real eye opener. Make sure you pay attention to aftermarket cables, including power cords. The system would love that stuff. If you have not yet done that, you have a lot of improvements to come, and you would not be close to your best sound yet.  :) 

While what you are doing is not considered by most to be a severely compromised audiophile setup, I get it. I have done similar things in the past, and the fact is that certain aspects of audiophile sound improve with such a setup while others diminish. It's a matter of taste which ones you prefer. 
What you have done is similar to a Line Source speaker, a popular genre of speaker that utilizes many drivers of various sizes. No wonder you feel the sound is great. 

What's nice is that you can swap back to the "purist" speaker setup with one or the other anytime you want. You have a variety of "best of all worlds" going at the moment. Kudos! Keep trying different amps, power cords, placement etc. because it all can be dialed in much more than you may suspect. If I had that setup I would try turning the smaller speakers around to fire backwards, just to see what the result would be. I would position the front baffle of the smaller speakers in line with the back of the larger speakers, so that it would be a quasi-dipole effect. I'll bet it would offer yet another interesting result. If I had the time and inclination I would try the smaller speakers turned backwards first outside of the larger, then inside of the larger speakers. Of course it's not "audiophile approved" system building, but there are no audiophile police who will knock at your door. :)

It's always great when you can experiment without cost. You also will learn much about the nuances/effects, good and bad, about such systems. You are one of the very few people who have the creativity and boldness to try such setups. It's obvious why you feel you are being rewarded. But, do not be shocked at this prediction; I suspect that over time (years) you may gravitate back toward a more purist approach with an even better single speaker and electronics. Perhaps you will turn into a hard-core panel speaker fan, as they have a lot of the openness that you are hearing. Lot's of directions to go! It's pure fun for me to see someone with an open mind and the will to be a system explorer. An audio system can be a play land that brings immense fun and joy. 

Glance at my Virtual System to see my enjoyment of variety and some alternative placement.

Doug, thank you so much for your compliments, insight and positive feedback.  I was worried I’d receive the equivalent of an (audiophile) public stoning!  

Yes, I’ve upgraded to acoustic Zen’s Gargantuan power cords.  They did make a big difference. ( Mr. Lee let me demo them first and once installed their effect on the sound was obvious, otherwise I would have returned them).  I appreciate all of your suggestions and will continue to experiment.

I did look at your many incredible systems and I am floored!  And I thought I was fortunate!  If only you lived in Upstate New York, I ‘m certain we could be best of friends.  

Thank you again.

"What labels?"

Oh Oh, folks coming out of the woodworks with their fond memories, before they became full fledged audiophiles...