Calculating box size for two subs

[neonblack 10+ year member]

Are there any calculators around for designing enclosure specs for two subs (8" ea.)? Haven't found any doing a search.

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[Jeffdachef 5,000+ posts]

Are there any calculators around for designing enclosure specs for two subs (8" ea.)? Haven't found any doing a search.

Subwoofer Enclosure Calculators, Parallel, Series, Port Length and Volume

 

[neonblack 10+ year member]

I can calculate the volume of a box. I have a mechanical engineering degree.

Just double the manufacturer's recommended box size (ported) for 1 sub? (Then calculate port size for two sub box size, of course.)

 

[Jeffdachef 5,000+ posts]

I can calculate the volume of a box. I have a mechanical engineering degree.
Just double the manufacturer's recommended box size (ported) for 1 sub? (Then calculate port size for two sub box size, of course.)

If you are building a ported box, you'll need a lot more then that basic calculator.

Look up how to use winisd on youtube and it should be the first 21 minute long video by showtime spl. Its free and you can plug in the subwoofer's thiele small parameters and play around with size and tuning and it will show a frequency response curve to give you an idea of how the sub will sound.

Only thing you need to figure out is the final cutsheet and how much port area you want for your box. its usually 12-16 square inches of port per cubic feet with 16 for more boomy and 12 for more flat but toned down sound. Dont go too low because you might get port noise which sounds really nasty.

This part's after you watch the video

You'd want to get your max dimensions and calculate your gross cubic feet after accounting in MDF thickness and subtract around 20% of that total and that 20% is a rough estimate for your port area and the number leftover should be close to your net cubic feet, then you plug those numbers into winisd. Of course after you are done plugging numbers in, it'll give you port length according to your specified tuning. Use that along with your height and width to get the cubic feet and subtract that from your gross cubic feet and you'll get a more accurate Net cubic feet number.

keep in mind this will model how the subwoofer sounds in that specific box but it does not model how it would sound in your car accounting in cabin gain but it should sound miles better then a prefab ported box or your own guestimate.