Sorry for misunderstanding, I did not get your correctly. For some reason I understood that you used 1601 in the 150hz tractrix and I was thinking the hell you were taking about.
I do use 8” driver too for my upper bass 140hz tractrix (107hz in the room) and was looking in past at the REPS but never made myself to get it. I do not exactly subscribe the full rage-drivers BS, and as many installations I have heard with REPS, I always was revolted with the front radiated full-range upper-mid noise and back loaded so-called “horn” junk. I use my upper bass driver from 100 to 1000hz but whatever I heard with REPS was virtually unlistenable under 300hZ. Well, I understand that in most of the cases it was not the fault of the REPS driver but the typical unintelligent enclosures the audio hoodlums spread around but those experiences with back loaded fart-machines made me do not try the REPS…
BTW, do you know any 4” output good upper bass driver (a compression or conventional)? It should have paper none-treated diaphragm, stiff paper suspension, high sensitivity and low excursions, to be underhanded … did I mention the correct tone? :-) Please the M4 and the similar dreck do not even mention.. we are not in Kansas ….
Rgs,
Romy the Cat