88rxn/a

i don't understand what dimensions i need?

someone gave me a BRAND NEW old school crystal 12 inch sub!! hes had it sitting around forever...
its a crystal CSe 12
i found the web site with this info:

• Fs 21.7 Hz
• VAS 3.65 Cu Ft
• Power Handling 400 watts
• Qts .36
• SPL 86 dB

i tried using a speaker box design from:
http://www.diyaudioandvideo.com/FAQ/Build/

using the speaker box calculator:
http://www.diyaudioandvideo.com/Calculator/Box/

i attached the result i got, but i dont understand any of it?? i just want a speaker box for under the seat of my 2004 SCAB!

can anyone help?

Sealed Box

Vas = 3.65 ft^3
fs = 21.7 Hz
Qts = 0.36
Qtc = 0.707
Dimensions
Vb = 1.28 ft^3
= L x W x H
f3 = 42.62 Hz
fb = 42.62 Hz

GATORB8

I like Crystal stuff, I had a set of their components in my old 4runner back in college.

Fs is the subs resonant frequency
Fb is the boxs resonant frequency
F3 is the frequency at which the output of the sub is -3 db (half as loud)
The Qs are the sub's tendency to resonate at Fs
Vas is how much air is equal to the sub's suspension "springiness"

Now that you sorta know that (just for background) on to the important number: Vb (volume of box)

You need 1.28 cubic feet of air space inside of the sealed box for this sub, this doesn't take into acount the MDF you have to use to make the box or the about .07 ft^3 for the sub's magnet and basket. Basically this bad boy is going to take up almost everything you got under the rear seat. You can cheat this number by stuffing the thing with polyfill (probably let you get down to around 1.1 ft^3).

You'll need to design this thing like one of the dual 10 pre fab boxes, but only one sub cut out and no divider, so that this 12 sees all of the volume.

Use 3/4" mdf if you can (you can get it at lowes/hd) and glue and screw your joints. You can use the basic length x width x height = volume to get the size figured out.

joefox

That sub is not a shallow sub so you'll probably end up having to make a box for on top of your seat.
If you still want to make a sub box for under the seat remember that the baffle needs to be 2" from the floor.
The box for this truck is very thin but 48" wide x 18" deep so going with 1/2" MDF will give you a .25 cubic ft gain in air volume. Just put 3 picture frame braces across the box. That's basically a divider with the middle cut out. The box would be 48" wide so 3 of them would give you a brace every 12" and the box will be more rigid than a 3/4" nonreinforced box.

My recommendation would be to save that sub for another install and just buy the right sub and box to begin with. When you consider the time and money spent installing amps, radio, & highs then the time and materials to build a sub box. A free sub can be expensive when it turns out that it isn't right for your truck and you have to throw that box away start over because it doesn't sound good.

88rxn/a

thanks, i sent you a PM...

Drolle42

Can anyone design a sealed speaker box with correct demensions to mount on bottom of seat and fit underneath. (I want to be able to have seat down and also lift up) Thks.
D