Verified answer

Are you trying to port a sealed enclosure or build a ported enclosure? It is going to be much more difficult to port a sealed enclosure then to build a new enclosure.

To correctly tune an enclosure you need to know what sub you are using as well as what volume you need. The port needs to be designed to fit your sub's specific needs. It needs to be tuned to a frequency that works best for both the sound you are looking for and the sub you are using. 30-35Hz is usually good for most subs but it is usually best for sound quality. It is kind of low if you are looking only for output and loudness.

To tune a port you need to consider how large the internal volume is (not including the port) and how powerful the sub is. A powerful sub is going to need a larger cross sectional area so there is no port noise. But a port that has a large cross sectional area is going to need to be longer. The trick is to find the best mix between the two.

An enclosure designing program such as WinISD is going to be the best for designing a port. That is a free program that you can download and figure out what size port to make. It will take some getting use to to figure out how to use the program correctly though.

Like said before, there are a lot of things you need to know when designing a ported enclosure.

Good Luck!!!

Speaker Box Port

step by step instructions...nice. i can try....

fist you need to know tha calculation to finding port length....

Lv = [(14630000 x R^2) / (Fb^2 x Vb)] - 1.463 x R

Lv = port length

Fb = tuning freq.

Vb = box volume (in cubic INCHES)

R = port ardius (if using a square/slot port the: R = sq.rt. A/Pi)

you will need to determine the size of the box you can fit in you vehicle. then see what the sub requires. a general rule of thumb is to use 12-16sq" of port opening per 1cu' of box space. once you find your port area, pick a tuning freq. (30-38Hz) then using the calc., plug in your numbers to find the port length. once you get you length, find the port's volume (subtract the thickness of the front of the box from teh length, this does not count. also add the thicknedd of the port wall....if it shares a wll with the box, don't count that side.) once you find you port volume, add it, along with the sub displacement, to the required volume the subs needs. (eg: sub requires 2cu' and has 0.12cu' of displacement....the port if 0.2cu'...total box internal volumen will be 2 + 0.12 + 0.2 = 2.32cu') build you box to this total volume...remember, this is internal volume...if using 3/4" (which you should be) add 1.5 to L, W and H to get you external dimensions.

if the port needs to bend, remember to always measure down the center (if you port is 20" long and you box is only 10" deep and the port is 2" wide.....you will need a port wall that goes back 8" and then over 10"...measuring down the center you will get 20".) always stay as far away from the back of the box as the port is wide. maintaining the squareness of the port is crucial.

there is a lot more to building but this is the basic....if you have Q's...lmk

Are you development a bandpass or ported enclosure? 4th order? 6th order? i'd propose you obtain WinISD, plug the T/S parameters in to your subs and initiate tweaking from there. there is not any one answer. each sub has it incredibly is own standards.