Wow! You guys have been busy, LOL. I go away with the flu for about 5 days and the post has gone crazy. Heheheh.
Anyway, barely feeling alive, but will chime in..
Answers to some of the questions previously asked...Regarding my versions and rebuilds...
Freq response is down to 30 Hz, actually lower, but conservatively rated. Free air is at 25 Hz.
High end is extended to above 20KHz.
Nominal impedance is 6 ohms.
VC's will handle 150 watts RMS at 300 Deg. C.
I do not recommend them for levels sustained above 96 db with HEAVY base passages, without heavy base they will do 98 to 100 easily. This is at 12 feet from the speakers! I find them to be plenty loud. This level I attain using less than 10 watts. These speakers have an Xmax of about 10 to 12 mm. Exceeding this will damge them as with any driver blown beyond its limits.
The original drivers were not truly designed as underhung motor assemblies and some were pre-loaded. The weight of the cone and the sloppy spider caused the VC to hang out of the magnetic gap and seriously reduced the efficiency of the speaker and its capabilities. Proper underhung design and a few tricks to deal with the weight have changed this problem and now the speakers get quite loud with minimal inputs. They do sound best however when driven with amps capable of considerable dynamic headroom.
I would recommend a room of at least 300 sq. ft. for the TLS-I and 500 sq. ft. or more for the TLS-II.
I do not recommend less than 100 watts per channel TUBE or 300 watts SS for the TLS-I and much more for the TLS-II. (Or the F's or the A's) They do not need it to voice or even sound good, but the dynamic head room works wonders. They just open up.
The best room placements I have found seems to be about 8 feet from center to center of the cones and at least 3.5 feet away from the rear wall and 3 feet from the corners. Corner bass traps and rear wall reflection control works well. Placing a flat screen TV on the wall or between them may cause some issues, or degrade sound.
The soundstage depth can be controlled somewhat by the closeness to the rear wall.
BTW, John Strohbeen is not the original designer of the A's or the F's. Lincoln Walsh discovered the concept and the founder of Ohm Acoustics, Marty Gerstin designed the A's with Walsh's help. The firt "A" was released in 1971 just after Lincoln Walsh passed away. Sadly, He never got to see or hear his creation. Marty Gerstin, then went on further refine the A's and to develope the "F", relesed in 1972, as a little brother to the "A". Again, further refining the concepts gained from the originals. The "F" was smaller and easier to drive, but did not have the full sonic merits of the "A's" which had and have no comparrison.
Though the cones were 3 times as heavy and they were very power hungry, they could produce bass that would involuntarily relieve a person as well as cause some damages to home objects. Yet they had a very delicate and nuanced high end. The later coment was not necessisarilly documented by Ohm, but was experienced by others and myself in the early years.
Marty is also responsible for designing the unsual and special voice coils that made the "A" and "F" possible. This concept was pattented as well.
John Stohbeen, the former owner of Tech Hi-Fi aquired Ohm Acoustics from Marty between 76 and 78. Through some of Johns efforts, the "F" was redesigned and or went through changes, until it was retired in 84. John then came up with and patented the idea now embodying the current Ohm products.
The most unfortunate problem now plaguing most people is that there have not been any of these speakers remaing in pristine condition or properly rebuilt from which to compare current product or the originals. The others whom have actually heard the originals are relying on fading memories, as these are 30 to 35 years ago.
Even I can't remeber those experiences, except to say that the original "A" and "F" set me on this path and BLEW me away forever.
Refurbished and upgraded F's start at $6K, ...A's at $13.5K
New TLS-I @ $8K.....New TLS-II @ 15K
Good listening to all,
Dale.