On another thread I mentioned that I was listening to my 2450's with SL diaphragms, and Z-man asked:
So here goes:
I have them on 2311's in my 4345's. Ya, they fit. They are almost an inch smaller than the 2441 (which I believe was tried by Bo), and the fattest part is just aft of the dog box for the 2122.
Both the diaphragms were new, and I believe there was a break-in period, though a rather steep one. They don't seem to be changing much now after about twenty or thirty hours of listening.
I plan to go back to the original 2421's when my new diaphragms get here. I've been experimenting while waiting. The old diaphragms in the original drivers were exhibiting some of the characteristics of fatigued aluminum.
I like the aquaplas coated titanium 4" driver. Of course there are a couple of aspects of what I'm doing that make any conclusions difficult, to say the least. 1) I'm plugging and playing with the stock networks. With the current substitution that probably means that the frequency balance of this portion of the frequency range has been shifted downward a bit. 2) the 2311 horn may be acoustically different from the 2307. Taking those unknowns into consideration, I'll say that I like the sound of this combination. It's not as warm as I like, but it is listenable at high volume, which I cannot say for all compression drivers and horns I've heard.
I've also experimented with a pair of refurbed TAD 2001's on 2307's. Those I like very much, although they do not seem to respond well to high levels. (Widget says the diaphragms may not be seated correctly). At lower volume they are quite marvelous. That aside, I'll say that beryllium seems to be the bee's knees. It is the only driver I've listened to that did not make it difficult to balance the imaging and harshness. That is to say, with other CD/horn setups I've always had to work with the levels to find a compromise between tizz and hash on the one hand and letting the imaging recede into the speakers on the other. I'm guessing that with these drivers on the stock network the frequency balance would be shifted upward slightly. The detail and lifelikeness with beryllium comes through nonetheless.
I never heard anything objectionable with the 2420's in my 4333A's, and I'm hoping the same will be true with the new diaphragms in my 2421's. I am aware that some people prefer the 2420 to the 2421, though. Anyway, we'll see.
I believe some of the Australian members with 43XX monitors are using 2425's with titanium diaphragms and find them to be good. I may have a go at that before I revert to standard form.
David