I have just been so very lucky to try out first the JBL S3100 then S2600 and 4430. For many years I have had B&W 801F and been very pleased with their sound, not their efficiency at 82db. I have been dreaming about the S3100 ever since I heard it very shortly in a shop here in Denmark back in 1997.
Since I thought it would me too expensive for me I kept searcing the Internet for its little brother S2600. But suddenly last month I found a pair of S3100, bought them at a very reasonable price and took them home.
My living room is 4x4.5m an I am app. 2.5m from the speakers, they have app. 2m between them.
Sound was amazing, with a huge soundstage (compared to the 801F) and an attack/dynamics I have never experienced before. They could sound a little edgy on my Aragon 4004mkII/Aragon 24k amp, but when hooked up to Threshold Fet Ten and SA/3 there was nothing to complain about.
But these speakers are absolutely huge, and I felt they looked too big in my small room. So there I was, having found the ultimate speakers but not liking their BIG looks.
I sold them to a guy in Portugal and found myself a pair of S2600 (actually just 25km from my home) at the same price. I took them home and hooked them up to my Thresholds, and a bit disappointed I was. They had the same great midrange as S3100, better bass, they where smoother (never edgy), but didn't have quite the attack and soundstage of the S3100.
Well then lucky me. I was trying to sell my 801F and suddenly a guy called me up. He wanted to try these B&Ws since he had bought a pair of old JBLs that he never got around to fix. I asked what they were, and he told me they were 4430 in bad condition and in need of new foam surround on the woofers. We agreed to make an even swap. Both were happy and exited. 2 days ago I got in my 4430 with new surround on them (cost me 150 euro plus 3 hours driving).
I hooked them up and listened with my eyes closed. WAUW. I had to open my eyes and make sure they weren't S3100. They had the bass, attack, soundstage and dynamics just like the S3100, only difference was:
S3100 can sound edgy when played loud
4430 can have that horn sound when played loud (they actually sound awful when played really loud, where both S2600 and S3100 can play very loud without sounding bad).
Now I also tried S2600 and 4430 on Luxman SQ38FD, Luxman SQ38 signature and finally Rogers E20a tubeamps (I really wanted to be Japanese and sat on the floor). Amazing sound. the best I have ever had. I Thank the Gods for Horns and Tubes....(and for giving us Count Basie & Ella Fitzgerald).