OK - I've collected all the drivers and am almost ready to start building a custom 4-way system. Please don't suggest different drivers - there will always be something better, but I really want to satisfy my curiosity using the following combination, and they're what I've got:
2105H or 104H-2
The closest JBL systems I've seen are the 4315B and 4343/4345, though obviously I won't be using the horn.
I really want to end up with a completely passive system, but due to the power hungry Sub1500's I'll also leave the bi-amp option open.
Below is a front view of what I've come up with. It's almost exactly the same size as the 4315B at about 33" x 20.5", (w/o base), but deeper at 16". This leaves me with ~ 3.5 cu. ft. for LF. Two 3" ports about 10" long will tune the box to ~ 28 hz, resulting in a system essentially flat to 30 hz.
My first question is what people think of the physcal layout? Rather than putting the main drivers in all vertical alignment I figured this arrangement would result in a closer point source. Opinions?
Second - in a .3 cu.ft. box tuned to 75 hz the JBL specs for the 2012H show essentially flat response down to 100 hz. Without the port it appears as low as I can get is 300 hz @-3db. Are there any ramification using a small port in the 2012H box? Even though the frequency plots of the Sub1500 show it essentially flat to ~ 300hz, I'd obviously like to cross over lower.
Third - crossover to the 2105H/104H2. The 4315B crosses over at 2Khz, but I'm thinking with the 2012H i might want something lower, closer to 1Khz, as in the L65A. And due to the efficiency of the 2012H it'll obviously have to be padded down.
Fourth - 'still deciding on whether the 2105H or 104H-2 will sound better. The curves Giskard posted make me wonder, though sticking with the 2105H/2405H combination would make using the HF section of the 4315B crossover mostly a no-brainer.
And last, (for now) - I'm not sure about crossing over to the 2105H at 8Khz, even though the 4315B does. It just looks like the crossover would be smoother if it were in the 6Khz range, (6.5Khz in the L65A). I've also got some 2404H-1's I can play with...
Anyway, I just wanted to get some opinion before I start putting this together. Obviously, the crossover will be the biggest challenge, but I'm in no hurry, and just want to get started in the right direction.