Hi, I am trying to add a 12" Audiobahn Excursion subwoofer to my 1999 mustang GT, but I am having a really hard time trying to figure out the right box specifications for my trunk. The subwoofer manual does not give me any exact measurements for a box, so I am trying to figure out box volume and air space and what not. I could really use a hand figuring this out. My trunk still has the factory mach 460 amp rack in the back, so I will only have roughly 11" height clearance for the box, so it will have to be angled. The manual gives me some information about the different requirements for the boxes, but I have not had a lot of luck calculating everything. Here is the basic info they give me in the manual...Very confusing.

Audiobahn Woofer Parameters
Vas does not represent the volume of a Box. Vas is just a parameter used when calculating a box.
Fs - 32.4 Hz
Qts - 0.39
Qes - 0.42
Qms - 4.43
Vas (Liters) - 45 Liters
Vas (Cu. Ft.) - 1.6 Cu.Ft.
Re - 3.25 ohms
Le - 2.55 mH
Mmd - 185 grams
Xmax - +/- 9 mm
RMS - 500 Watts
Sd - 0.045 M2
Freq. Resp. - 26Hz-1kHz
Efficiency - 92.8 dB

An EBP of less then 45 is SUGGESTED for only a sealed box and greater then 65 for a ported box.
EBP - 77

Audiobahn Woofer Parameters
Depth - 5 3/8"
Hole - 10 7/8"
Diameter - 12 1/2"
Displacement - 0.15 Cu.Ft.

[align=left]Space Saver Bass Design
[/align] Ported
Air Space (Cu. Ft.) - 1.3
Port Size (Inches) - 3 x 7.75
Port Vel. (%) - 18.59
-3dB (Hz) - 35
Tune Freq. (Hz) - 38
Sub Disp. (Cu. Ft.) - 0.15
Port Disp.(Cu. Ft.) - 0.028
Total Vol. (Cu. Ft.) - 1.5

Everyday Bass Performer
Ported
Air Space (Cu. Ft.) - 2.25
Port Size (Inches) - (2) 3 x 9
Port Vel. (%) - 9.64
-3dB (Hz) - 32
Tune Freq. (Hz) - 37
Sub Disp. (Cu. Ft.) - 0.15
Port Disp.(Cu. Ft.) - 0.067
Total Vol. (Cu. Ft.) - 2.5

Sealed (Not Recommended)
Minimum (Cu. Ft.) - 0.25
Maximum (Cu. Ft.) - 1
SPL (dB) - 87.5

 

Why isn't sealed recommended? Hmmm sounds shady to me

Anyway you can calculate volume pretty simply. Easy one do a perfectly square box, 12x12x12. And actually do the math that way multiple you WxDxH. you will end up with 1728. Then you always no matter what your number is from that divide by 1728, and since this is obviously 12x12x12 box it is 1 cubic foot of airspace (remember that needs to be internal measurements by the way) take another box. 12x18x20= 4320... 4320/1728=2.5, therefor you have a 2.5 cubic foot box. Adding angles is when your calculations get tricky. Some people will just guesstimate taking out the angle. I am yet to do a box with angles so I really dont have the calcualtion memorized, but I do know there are alot of websites out there that actually have calculators on the site that will show you what you volume is with the dimensions you input.

 

Here is a 1.3 cubic ft box design I did that fits perfectly with the sub facing foward.

 

The excursion on those subwoofers is 9mm?

Hmmm this $25 12" has 9.1mm http://www.edesignaudio.com/edv2/pro...roducts_id=183

Can't move much air with that kind of excursion, less air movement, less SPL... [sm=smiley7.gif]

Wild guess here.......... You paid more than $25 for those didn't you?

 

yeah but his sub bling blings

 

True dat.

 

as far as the excursion goes, the audiobahn is actually 18mm, they just have it as a +/- figure...where most companies go from peak to peak...and have you ever thought about an upward facing box? would be fairly easy to make under 11" and with only one sub, it wouldnt take ALL your trunk space.

so a 1.3 cuft box could be 8" tall (leaving space for the sub to move, facing upward) by 20" wide by 18" deep
use 3/4" MDF and youll come out to just over 1.3

or a 2.25 could be 10" tall X 24" wide X 20" Deep...2.28ish...but use 1/2" MDF

and with either of these, there will be enough extra suface area to place your ports almost wherever you want them.

or you could always fiberglass it in for a nice custom install
[align=left] [/align]

 

There are very few companies that do their ratings in peak to peak. XMAX is linear one way excursion.

So your Audiobahn is 18mm peak to peak and 9mm one way linear xmax.