I had posted these a while ago, under another topic, but they bear a replay, even though they're not things of beauty.
These are an unusual 1950s design by John Karlson and Wayne Green (of 73 Ham Radio Magazine infamy) and with better (and more modern) drivers, they sound fantastic, and are extremely efficient. The cabinet's internal design goes against all "conventional wisdom".
and a peek inside with the grille removed:
The 12 inch driver is a Pyle Professional PYM1298, from Parts Express, which is a re-branded and lower cost Eminence Kappa-12. Efficiency is very high, at least 98 dB SPL. THe horn is a vintage Altec Lansing 811B, with 806-8A compression driver and N801-8A dividing network (their name for a crossover). I had bought these new back in 1973.
The one major flaw with the original Karlson design, using a full-range or coaxial speaker, was that the response above 1KHz could be harsh and "shouty". Placing the HF driver on top eliminates the problem.
The best part was, some one else did all the "dog work" for me about 40 or 50 years ago, and I "adopted" these for free at the local town dump's swap area. The original UTAH FR speakers were absolutely shot, and it took me about a year of dithering around before I finally took the plunge and fixed them up. There are other views of the insides of the cabs elsewhere on this site, under "Old Speaker Design".
/ed B in NH