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)
The only thing even close were Tannoy Autograph Pros (dual 15" dc)