vintage Rockford Fosgate home enclosure dimensions help

[inkreus]

Dear friends,
I have a car vintage sub Rockford RFA412 and built a sealed enclosure for it following the instructions/dimensions on its owners manual. I have been using it for a long time and very satisfied. I am changing my room and I would like to built a new enclosure changing the measures of my sub from rectangular design (dimensions given by owners manual) to a cubic design. Unfortunatelly I don't have experience to calculate the new dimensions to obtain same size for all sides.
Actual dimensions are 13.5"high X 7.75"width X 20.5"length = .88cu.ft

Which dimensions I have to use to obtain same size on all sizes? Or at least in front? Considering minimum of 13.5" in front size due to the speaker size. The most important is to mantain the .88cuft.
Could someone calculate and tell me the measures?

[dangus]

If you don't have a scientific calculator, slide rule, log tables, or spreadsheet handy, you can use trial and error with a four-function calculator. It takes surprisingly few guesses to get close enough.

[TheBaronGroog]

13.5 x 7.75 x 20.5= 2144.8125 cubic inches = 1.241cf total volume.

I'd presume it's made out of 3/4" MDF or ply, so that would give an internal volume of 0.825cf or 0.845cf if made from 18mm MDF or PLY.

For the same gross volume (of your current box) your cube needs to be 12.9" x12.9" x12.9"

For 0.88cf internal volume and 18mm MDF or PLY you'd need 12.92" or if you're using 3/4" MDF or PLY13"

[Brian Steele]

Originally Posted by inkreus

Dear friends,
I have a car vintage sub Rockford RFA412 and built a sealed enclosure for it following the instructions/dimensions on its owners manual. I have been using it for a long time and very satisfied. I am changing my room and I would like to built a new enclosure changing the measures of my sub from rectangular design (dimensions given by owners manual) to a cubic design. Unfortunatelly I don't have experience to calculate the new dimensions to obtain same size for all sides.
Actual dimensions are 13.5"high X 7.75"width X 20.5"length = .88cu.ft

Which dimensions I have to use to obtain same size on all sizes? Or at least in front? Considering minimum of 13.5" in front size due to the speaker size. The most important is to mantain the .88cuft.
Could someone calculate and tell me the measures?

Sounds like you're using a car audio driver for home subwoofer duty. If that's the case, I suggest going with a larger sealed box. The sealed box suggestions for car audio duty usually lean towards smaller box sizes for better power handling and easier fit into the vehicle, at the expense of "Q" and low frequency performance.

Do you have the t/s parameters for the RFA412?