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jblayz1
10-14-2007, 01:18 PM
i'm thinking of making a ported box 2 cu. @ 31 hz here are the dimensions i'm thinking.

width- 17"
depth- 19"
height- 16.5"
without a port i figured the cu. is 2.348

what i can't figure out is the dimensions i would need a round 4" port to be in order to tune it to 30-32 hz. i'm thinking side port, maybe... and the sub facing rear. i tried it calculating a square port, no dice. can't get it to tune low enough.

jblayz1
10-14-2007, 02:45 PM
or i could do two 2" ports but i don't know what length they need to be...

mazdakid
10-14-2007, 03:36 PM
2 4"
the 2 2" wont be enough
a single 4" probably wont be either but around 14" long would be 31hz

jblayz1
10-14-2007, 04:20 PM
how about two 4" round, 7" long ports facing the cab and the sub facing the rear ? would that make this enclosure 2 cu. @ 31hz ?

Immacomputer
10-14-2007, 04:46 PM
how about two 4" round, 7" long ports facing the cab and the sub facing the rear ? would that make this enclosure 2 cu. @ 31hz ?

No. You doubled the amount of port area which means you need to increase the lengths.

If you do 2 4" ports, you would need to make them 31.5" long EACH. I don't see that happening in your enclosure unless they're external.

jblayz1
10-14-2007, 04:54 PM
**** it. backwards numbers again. seems to happen often in car audio.

ok, so would i need to do one or two ports and what sizes?

Immacomputer
10-14-2007, 05:06 PM
What sub and what kind of power?

jblayz1
10-14-2007, 05:35 PM
12" tc3k hybrid and re 12.1 1200@1 ohm. i could do it this way (http://www.subwoofertools.com/forum/...&Vas=&Fs=&CE=0) too. but the enclosure is humungus..LOL.