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DeepMag1c
12-25-2004, 09:56 AM
Im building a box for 4 15 comp Vrs using Georges step by step guide

http://forums.caraudio.com/vb/showthread.php?t=74715

how do i look so far? I think my math is kind of off.

Box for 4 Comp Vr 15s

Box Height- 33, Internal Box Height- 33-1.5 =31.5
Box Width - 55, Internal Box Width- 55-1.5 = 53.5
Port -30 Widthx 4 Height

Figure out port length using this formula
Lv = Av*1.84*10^8/[Vb*1728*(Fb/0.159)^2] - 0.823*sqrt(Av)

120*1.84*10^8/[25*1728*(32/0.159)^2] – 0.823*sqrt(120)
120*1.84*10^8/[25*1728*40505]– 0.823*sqrt(120)
120*1.84*10^8/1749816000– 0.823*sqrt(120)
12.6184-9.0118=3.6

Lv=3.6

subtract half of your port width from your port length(Lv) to get physical Lv
(half port width)15-3.6 Plv=11.4

pick ANY number shorter than pLv.
2nd wall =5

take your physical Lv and subtract the external depth ( the number you decided on in the previous step +1.5" for the mdf.)
11.4-6.5=4.9

take this length and multiply it by your port width+.75 and then multiply it by your internal height and finally divide by 1728. this gives you the displacement.
4.9*4.75*23.3*31.5/1728 = 9.88 displacement

DeepMag1c
12-25-2004, 07:52 PM
ttt

DeepMag1c
12-27-2004, 04:10 AM
ttt......