how to determine port length for 2 pipe ports

[dsw422]

Yup, less port area = shorter port, that's how it works.

Since you are going to use the two 3" ports, let me tell you what's going to happen. At low volume its going to work just fine. However once enough power is put to that sub the port velocity is going to get too high, you will probably get port noise, and port compression. Port compression is going to make that box begin to function like a leaky sealed box. Impedance will rise, cone excursion will increase, and output will diminish.

ugh.. ok.. ill go with 2 4 inch ports.. what length will i need?? ill maybe have them stick out from the box so i can get correct length.. how would u make it look good like that?? this box is going in a show vehicle...

oh and since JoeX recommends a lower tuning, could i get lengths for 40hz, 35hz, and 32hz?? ill decide when i see the lengths

[MrSkippyJ]

If you invert the sub it will help make the ports that extend out not look out of place.

[dsw422]

If you invert the sub it will help make the ports that extend out not look out of place.

cant invert the sub due to the back glass of the hatch.. plus i dont think it is even invertable.. but id love to do it.. lol

[MrSkippyJ]

do you have enough room between the back glass and the box for external ports?

[dsw422]

do you have enough room between the back glass and the box for external ports?

i hope so.. but i could b wrong about the back glass.. now that i think of it.. the sub and ports should b close to parallel with the glass... but im sure the sub cant b inverted.. and im hoping the length of the port sticking out isnt too much either.. like i said, this is going in a show car

[MrSkippyJ]

what about finding a sub that works in that airspace sealed?

or just shrinking it down and making it sealed for that sub?

[dsw422]

what about finding a sub that works in that airspace sealed?

or just shrinking it down and making it sealed for that sub?

b/c im building this for another person.. he already has the sub and amp and wants ported... how much more low end(output) difference is there between a sealed and ported box??

[MrSkippyJ]

you will lost output overall with a sealed box, but sealed boxes can play low too.

[dsw422]

you will lost output overall with a sealed box, but sealed boxes can play low too.

if i go sealed, ill have to reduce the interior volume right??

[MrSkippyJ]

with the same sub, more than likely. But that is a relatively easy thing to do.

with a different sub it just depends.