Can someone help me design a box?
 

I just need to know the volume needed to obtain an optimally flat response -in car- for a sealed enclosure. that means calculated with cabin gain. I have a protege wagon if cabin size can be taken into account.

I just googled average interior volume of a car and hit wikiepedia.

http://en.wikipedia.org/wiki/Vehicle_size_class

Scroll down to USA regulations, small station wagon says under 130, over 120.

Anyway. I have a mac and am too lazy to drag the pc laptop out of the closet and find some software for it.

Here are the specs on my sub. I will be feeding it 300 watts.

Here are the technical specs;
Dual 4 ohm
Revc = 7.8 Ohm
Fo = 22.6 Hz
Sd = 350.0 cm^2
Krm = 2.1538m Ohm
Erm = 1.085
Kxm = 193.204m H
Exm = 0.588
Vas = 71.3 Ltr
Cms = 409.87u M/N
Mmd = 129.248m Kg
Mms = 133.013 g
BL = 19.032 T.M
Qms = 3.290
Qes = 0.37
Qts = 0.333
No = 0.22%
SPLo = 85.36 dB

Thanks in advance!

I have a mac and don't have virtual PC, so I can't use any of the free software online.

try taking a look, thats an online version of winisd

Hey, that's some handy page!

Now I can finallt get rid of this ol'PC. WinISD was like the last reason to keep this PC up and running!!

(Other audio/speaker stuff related MAc software hints are welcome, though!)

Thanks, Paul

Cabin gain is determined by the lengths of space inside the car, not volume. Give us the length and width of the internal cabin space and we can make a reasonable guess as to the cabin gain frequency.

Then you set F3 of the box to match this, with Qts dependent on sound preferences and length/width ratio of the cabin.

It is a mazda protega wagon. Full length is probably 10-11ft, width is 5ft.

That will give you 51-57Hz to aim for with Qts in the range 0.65-0.8

thanks