The best speaker you ever heard?

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.

disagree,

the amp & crossover components are far more important.

any 1-inch or less light weight diaphragm tweeter, with a lightweight but rigid 6.5 woofer,
both with strong magnets, hopefully with lightweight copper windings in the voice coil.

both in a 1.5cu.ft box vented and tunned to 20Hz, will sound great.
ofcourse the plastic box sounds diferent than wood box in the mids, also the foam inside to absorb the mids reflecting affects.
also trumpet vs. direct sounds diferent, specially in the mids and highs.

if the crossover, is properly designed passive,active or digital, and if the tweeter and woofer have the right physical separation needed for the crossover slopes to join properly, 6dB 1 slope needs more separation 12dB/18dB/24dB/48dB 5slope needs less physical separation between the woofer and tweeter.

etc...

passive crossovers when they heat sound diferent also.

the best combos:

spirit absolute zero + peavey cs200x, when brand new was amazing, 2 days later when they broke in, sounded totally diferent. had to sell them.

jbl 4343 + mcintosh c32/c33, had weird collapsing mids, but great everything.

purchased the jbl 2405h tweeter, just to found out that sounds totally diferent with a diferent amp & crossover.
with new diaphragms! broked-in.

tannoy system 2 with crown d75

most 6.5 + 1-inch loudspeakers have crossover points from 1.5khz to 3khz, from 6dB to 24dB oct. Q arround 0.7 BW.

its the kind of capacitors, or the kind of dsp algorithms, the amps or the diaphragm weight that makes them sound unique.

genelec 1031a its nice out of the box and broked-in

bigger diaphragms in the tweeter will give better mids arround 1.5Khz, but will give worse highs.

jbl l25p has a bit bigger than 1inch tweeter
also most quested, dynaudio and m.audio bx8a have 1.1-inch tweeter

1.75" tweeter have great mids but ugly highs.
same with woofers , 24 inch woofers have ugly mids.
15" have acceptable mids,
6.5 or 5.5 have great mids.

the magic its in the amps. + crossovers and diaphragm size and weight.
from JBL control 25av, to RCF, DAS audio spain, to QSC, EV, behringer truth black, krk rp5, alesis, quested, emu pm5, event, etc... anything with strong magnets, good xmax. good crossover, & nice amps.
will do just fine.

its nice to take a passive speaker and buy amps and a digital crossover, or digital EQ with filters, and by pass the passive crossover with your own digital settings.
and custom amps.