The best speaker you ever heard?

The question is fine, it basically asks what the best speaker is that YOU have heard. That means nobody can argue against that, EVER. It just says a lot about that responders personal experience. If Mr Tennis feels that the Quads are his best ever speakers he heard, well that's a reflection of his personal experience and taste. Who can argue with that? :-)

It pays to keep listening to different speaker systems and setups though, just to validate ones experience and understanding of how it impacts sound ... you do have the right to change you mind and/or taste! Especially with ever improving sound reproducing technologies and products. And Tbg, don't forget the room impact...

I don't know if it was the room, the source material, or the associated equipment, but I was once absolutely captivated by Meadowlark Blue Heron's and wished I could afford a pair at the time. I recall I was listening to Stevie Ray Vaughans / Tin Pan Alley via a Wilson Benesch Full Circle and VTL 5.5 Preamp. That cut is a classic if ever there was one.
I never did like Meadowlark's updated cabinet design. I wonder if that was part of their undoing.

HQD, the hartley-quad decca set-up Mark Levinson put together, many years ago at Lyric in New York.

B&W Nautilus (snail).

Yes,I heard the HQD at Lyric,and at a lucky friend's home,back then!Superb,BUT....

Though some may question my taste,or opinion,this weekend I had the GREAT pleasure of hearing a "highly modded" and tuned to the "N'th" degree set up which consisted of modded Infinity RS-1b's,CJ ART,Lyra Titan-i,etc componentry...

The subject of "BEST" must be in context of room/system/owner's skills.

This system was absolutely amazing,and we played incredible LP's ranging from string quartets to orchestral,to jazz.

You name it,"this" set-up did it,to the maxx!!

This system belongs to the GREAT SID MARKS,of TAS fame!!

A "classic gentleman",and connoseur of great music/sound,on the "best" lp's!!...

The guy IS a legend,and has proven it on countless times,but......I was unprepared for this level of improvement in his always superb/full range/dynamic set-up!!

AMAZING,and I was lucky to experience it!!!

Best to all!