2 18's > 3 15's & 4 12's. If you tune low and double the power you might hit the same numbers as 6 15's. I'll try to design you a slanted V-ish box for 4 18's, can't say I've ever made that many calculations before though. A week later.. lol. Can you fit 20.75" height because that would be ideal for 18's. Silverado boxes are 21" high.

Like this, only angled and done.

 

that last one looks nice

 

I have 18" high. It's a 94. I don't know why I even bothered with this thread. I do appriacte the help I've gotten from A few members on here though. The passthrough and the effect it has is what's confusing me. That link i posted is what I'd like to do. Minimal angles makes alot of sence tonme as well. In that link the subs are in 2.75 after per sub 10sq port to 32hz and the passthrough is tuned to 95hz. Is it simply 2 ported boxes, bandpass or something else. I'm aimed this thread to you Peter becuase both Tim and frank said your the man with powerbass and boxes. Good thing I didn't call you for the help inwas looking for eh. To rbgnwa45 yhanks for your help. 4-12's or 4-15'will be good.

 

Can you do something for 15's? I don't think 4 12's will get be to where i want to be.

 

It's a horn.

 

I like your previous design but in 15's or 12's.

 

I need an air space & port area recommendation for M or L series 15's before I can calculate angles.

 

L series 3 @ 40
M series 6 @ 35
that's what pb site says. Im going to have to model it in bb6p and see how it graphs. That box in the link I posted is 2.75/15 with 10sq port tuned to 36hz. 8 12's would be fun too.

 

*12-24 cf3. Seems like the M series has your lows covered.

This is an airspace calculation template that's supposed to be symmetrical.

 

Woah. That's a ton of math right there. 6cubes still seems large for a single 15 though.