need port sizes

[blearsy1]

first off this is great site got tones of info cool, but i need some help i've got 2 12" kicker l7 and i'm making a box that my max sizes are width-39", height-15", depth-18" so that's prob the most i can atleast get in my car with breathing space for the port, i wanna put a divider down the middle so each sub has its own space and then the port walls running along with the divider for each woofers area but i want the port tuned to around 37hz - 40hz so i don't know what length to make the port for it to go that range, like this picture but with the ports running from the middle thx any help appreciated

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[azimuth 5,000+ posts]

you would actually get louder and have better low end, by putting 1 of those in 3 cubes ported, then by putting 2 of them in under 4 cubes (under 2 cubes per sub). if you're bent on having 2, then there is a good chance that a simple sealed box for them, will sound better than a tiny ported box.

 

[blearsy1]

ok i understand that, but i've managed to make some room and have got a cuft of 6.47cuft divideded by 2 woofers which is 3.23cuft for each woofer and it recommends maximum of 3.25cuft for 1 l7 in a vented enclosure so all i need now is port length and width which i am having trouble trying to calculate here's my new sizes width-39.5", depth-20.5" and height-17" i still want the same design though if i need a bit more cuft i can extend the depth a bit more thanks for your help oh i want it tuned to around 33hz - 35hz now