The best speaker you ever heard?

wilson audio maxx 2 and marten design coltrane

The MBL 101, the Hansen king, amgico II as mini monitors...

Beveridge 2SW2 (coherency), Hill Plasmatronics (holographic imaging), Rogers LS3/5a - 15 ohm variety (my first foray, mid-late 70's, into high-end), mbl 101E (great system synergy in all mbl reference rig) and Bev Model III's (my current transducer).

In 1971 - 2-pairs of KLH9s, JanZen ESLs for center channel and ambience plus 2 K-horns used as subs. The K-horns had a high cutoff of 100 Hz and 40db of boost at 10Hz--I'm not making any of this up. Most will say that K-horns don't give any support below 40Hz--they might lose coupling with the room and they might lose efficiency but they will load the cone all the way down. In this case, the K-horns were transformed from a, say, 80% efficient speaker into a 0.1%, or so, efficent speaker. The effect was terrifying. Source was an Ampex 350 and 15ips dubs from the original masters.
The only thing even close were Tannoy Autograph Pros (dual 15" dc)

I think the Ohm Walsh line is still the best.