came up with this let me know if this is ok any and all help thanked in advance.
ext-18 (h) x 14- (d) x 40- (w)
int-16 (h) x 12- (d) x 38.5- (w)=
7392 cu in/4.277 cu ft/11977 litres
7392 x0.77 =5691.84 cu in (0.77=spk+port disp.
5 x corner dispersion(32 cu in ) =160 cu in
5691.84 -160 =5531.81 cu in /3.2 cu ft.
3.2 cu ft x 16 =51.22 sq in divided by 16 =3.2 inches wide =77mm port width.
internal L vol. box after spk/port/corn disp.
=3.2 cu ft
=5531.81cu in
=89.6 litres .

 

Ive got DD3515's and DD9515D, enclosure is tuned to 62Hz for my Fiat Uno (like a Fiat Panda) and my austin mini stationwagon. I'll be relocating to Alberta, but have to leave all my equipment in south africa. send me a pm, i email the box specs which i got from DDaudio.eu

Jsinn