Hi guys, last week I bought a pair of JBL 4691b boxes off Ebay. I was happy when they turned up as their condition was better than I expected. MMnn what to load them with? well I had a pair of 2231a drivers and 2420 compression drivers out of a pair of old 4331 monitors I also got off Ebay kicking around so they were the candidates. The boxes use a 2370 horn ( I don't hear much spoken about the 2370's but believe me they are brilliant with the 2420 ) the cd's took some getting into the boxes the cradles are designed for the later smaller drivers. I removed the original crossover networks (1500hz ) and fitted a pair of 3120a - 1200hz networks. The end resalt " WOW " the bass drivers seem to like the smaller enclosures ( 4cuft v's approx 5.5 cuft for the 4331's ).
The sound is so spacious and no real sweet spot which is nice. I coupled the 4691's with a pair of 2241's I have in 6 cuft bins tuned to 40hz, and crossed them at 100 hz. The bottom end is so full and warm I am so happy with the resalts. I am going to try a pair of 2220's in the bottom end to balance the system a little better as the efficientcy is down a little on the 2231's and a little more mid bass would be great. I'm also sourcing a pair of E-145's , I believe they work real nice at home.