The best speaker you ever heard?

The best speaker system I ever heard was the Wilson Audio WAMMs, years ago. They could reproduce the dynamics of a full-scale orchestra and still present a close approximation of the sound of real instruments.
But, the top of the line Soundlabs I've heard recently (Ultimate-1s, I think) are better at capturing the nuance of detail and the size and shape of the "acoustic image" of a real instrument's sound and are the best I know of, now, especially at anything other than ear-splittingly loud levels.

Avantgarde Trios, tough to beat good horn systems if you like the true dynamic range of music and not the possibly more "accurate" but compressed sound of most high end speakers.

VMPS RMX 'Elixir', I am fortunate to spend a couple hours each day with this system in our studio. While you may want to take this with a grain of salt since we peddle VMPS, I invite you to come listen and decide for yourself.

Regards,

Rupesh Kapadia
ROOP Audio Labs LLC

Those iddy biddy bose speakers

VMPS RM/X with Analysis Plus internal wire and TRT crossover capacitors. Passively biamped with Jeff Rowland 302/4 and sourced with dCs Verdi/Purcell/Elgar DSD stack. Powered with BPT 3.5 Signature. Pure Note Cerulean XLR interconnect, custom Acoustic Zen Hologram mk2 "Double Barrel Shotgun" speaker cables with 7n silver, and BMI Whale Supreme power cords. Room treatment by Acoustics First.

Second place: Apogee Diva with Muse 18 subwoofers, DAX3, Krell MDA-500 amps, Sonic Frontiers Trans3/Proc3 & Line3.