So i finally made my seccond DB last night, hooked it up, and, to say the least, wasn't satisfied with the results. the driver that i used was the aluminum cone audiobahn. i figured that if i got a beefier audiobahn then the one i had previously, then it would sound better, right? The one that i was using before seemed like a much weaker design. Smaller surround, paper cone, lighter magnet. Anyway, they both have an EBP in the 50's which would mean they're for vented boxes, and the aluminum has a really low Fs of 26hz. I played some sweeps and tones through it and it has great response in the 40-45hz range but almost nothing away from that peak.  there are nothing but rattles in the 20hz region, weak 30hz region, and anything above 60 or 70 is just nonexistent. Every cheep speaker that i play has great response in the 60-80 hz region this one had nothing.    I played music through it and the bass was conciderably behind the rest of the music.  It was slow. So how do i tune this thing to work with a driver like this?  Or should i go back to using the cheeper drivers?

The baffel is so tight that i have to sit on top of it to move it down, and yank up hard with all my might to move it up. i don't think that there is much air leaking around it

Thanks Ziggy for your replies.  Yeah i checked that baffel assembly already, this being my seccond box, i think i have a grasp of what i'm doing.  That panell F should have the point facing away from the half moon cutout.  anyway, from that diagram under 'explenation of how it works' the peak of the highest tuning was at around 100hz and very flat at the lowest tuning.   i fiddled around with it some more today and i kind of got it to sound a little better.  but mine is still extreemly peeked at 45 hz. makes it sound like a 1 note system, which is what i'm trying to get away from.
i don't know if anyone read my post a few months ago about putting 2 of these into a station wagon, anyway, maybe if i'll have some extra time this weekend, i'll do just that and post up my results and findings.  the trick will be to tune one to 45 and the other to 90.   or 40 and 80? or 30 and 60? i don't know yet anyway,
does anyone know of a program that i can put on my laptop other then soundforge that i can use to create a few sweeps and then test the response inide the car with a microphone?  it would be interesting to see a few charts of actuall responses in the real world instead of in a lab. anyway, im rambling on right now. heh let me keep quiet

[quote author=detenator  link=1130006618/0#4 date=1130024282]...........  the trick will be to tune one to 45 and the other to 90.   or 40 and 80? or 30 and 60? i don't know yet anyway, [/quote]
That would be about the best way to offset the inherent shortcomings of a 4th order design. Just don't tune them too far apart or you'll have the same one note response again, times 2.