Hokay... Ready to start designing a box for the new sub...
Only box calculator I've found so far is at http://www.subwoofertools.com/forum/ported-box.asp
The absolute maximum outside dimensions of this box cannot exceed 40 in. long x 22 in. height x 20 in. wide.
Which makes it just over 10 cu ft, OSM.
So, I played around a bit and made a second shape that adds an extra 1.5 cu ft, for a total of 11.5 OSM.
Oh now that I think about it, I could make that 22 height any height I want... up to say, 36 inches. Because I'm thinkin' for daily, the box will lie on it's side, sub facing rear doors. And for comps, I'll flip it on it's back so the sub is facing straight up. Window line is at 23 inches, so that's why I got 22 there. But the depth of 20 is more than safe, so ya... I could make this a lot bigger...
So nix that 22... let's make it............ 28... If I just make the square box... that's just under 13 cu ft, OSM.
Soooo....... I want this box just like my competition box for my 12" H2. Sub and dual ports facing up, so I can plug one for daily SQ.
I can build it, but I can't design it... I'm lousy at math...
Hopefully someone here can design it for me, right down to board cut sizes... Pretty please with sugar on top?
So, 40 L x 20 H x 28 W = 12.962962962962963 cu. ft. OSM. Both ports open, I'd like tuning at 50 or higher. 60 even. Plug one port, I'd like tuning 32-36 or so.
Here's a pic of my existing box that's about 3.5 cu ft, dual ported just like I want to do the new one...
(You can see more pics at http://firebase.com/grizzz/tuneweb/ )
Here's a rough sketch I just did of the new box:
I'll use 1 inch thick mdf, most likely. But it might just be 3/4. Should I get bracing in there too? It'll all get glued & screwed together, except the baffle board. It will be removable, sealed off with 5/32" weatherstripping (good thing I got that bigass roll when I built my last box eh?) so that needs to be take into consideration. And if the box performs well (which I assume it will) I'll get it sprayed with Line-X bedliner again. So that will add another 2 or 3 mm to everything... OH I'll want 45 degree angle boards in there too... If you lay the box on it's back, sub facing up, in the bottom of the ports I'll put in 45 degree angle boards, as well as the opposite end of the box. I did this to my existing box, and it gave me about another 1.5 dB
Here's some specs on my sub, I dunno what the depth one is (how deep the sub is), or how much space the sub itself uses up... But maybe it's in here, I dunno what all these specs mean...
Can't get this to post nice, but the info's there... Two different subs, so two different specs. And my exact sub isn't there, an APX18Q1.4, we gotta guess...
APX18Q2 APX18Q.5
Revc (ohms ) 2 2
Fo (Hz) 28.85 32.25
Sd (sqM) 0.1195 0.089
Bl (TM) 41.3 26.38
SPLo (dB) 94.9 95.67
Xmax (mm) 15 15
Dvc (mm) 75 75
Qms (m.q.) 5.72 5.39
Qes (e.q.) 0.26 0.2
Qts (totQ) 0.248 0.19
Vas (liter) 195 144
Cms (uM-N) 96 71
Mms (gram) 271 321
Oh, here's a couple "recommended" boxes by the manufacturer. They're designed for 5000 watts.
APX18-ported 6.0ft3 (40six10"long) ( 32Hz)=5000w (SB)
6.0ft3 ( 120six 1"long) ( 65Hz)=5000w (SPL)
Bandpass Rear Chamber:3.0ft3 sealed
Front Chamber: 6.0ft3 ( 100si x 8" long) (72Hz)
Bandwidth: 50-78Hz=5000W (SPL)
