port question

[raisefold 10+ year member]

Hey guys, I've been using subwoofer tools to design a sub box, but they have the slot port, which isnt really a problem, but I just measured the trunk of my car...and the box I designed to spec takes up half of my trunk. I really want to keep some of my trunk space...at least 2/3. The box I wanted was 2.5 cubes tuned at 32hz. the dimemsions were 33.5 x 15.5 x 16.

I was trying to explore options. I was looking at the 12volt website and I tried to use their port calculator. If i used 33 x 16 x 12 as external size, I get 2.775 cubic feet. with the subs (0.09) I get internal space of 2.595 cubes. So If i were to use a round port that is 4 inches in diameter and tune it to 32hz. Would the port be 9.8 inches long?

I'm just trying to understand the concept. Thanks in advance.

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[raisefold 10+ year member]

also...i noticed that if i have 1 4 inch port it would be around 9.8 inches...but if i add another 4 inch port..i would need more than double that length. i dont understand

 

[colgatekillaa 10+ year member]

http://www.darkscience.com.au/caraudiohowto/slotcalc/

plug some numbers in

 

[raisefold 10+ year member]

I just want to know if I have it right.

 

[xluben 10+ year member]

for a single 12" you'd want two 4" ports to avoid port nosie, and yes, the more port area you have the longer you need the ports.

so each port will have to be over twice that length.

 

[raisefold 10+ year member]

for a single 12" you'd want two 4" ports to avoid port nosie, and yes, the more port area you have the longer you need the ports.
so each port will have to be over twice that length.

i have 2 assassin 10s. I just want to save space in my trunk, but not have to give up so much space with a slot port

 

[xluben 10+ year member]

you still need (nearly) the same amount of port area (the flared ports willdecrease turbulence a bit) so port length will be nearly the same (and a round PVC port will have thinner walls, so that'll save a little more displacement).

all things considered aero ports will save a small amount of space, but they can be hard to fit in small boxes to get low enough tuning.

if you do decide to do aero's, i still think you should do at least two 4"

 

[raisefold 10+ year member]

according to psp-inc...for 2-4 inch aeroports...i need 24.53 inches each. so should i make the box bigger to compensate for 2 aeroports now? what size box would be nominal for those 2 ports?

 

[colgatekillaa 10+ year member]

what if you put them on the side of the box? would that change anything?

 

[colgatekillaa 10+ year member]

and also, quick question for my box, will 4 2 inch ports be enough or will i have to get bigger ports instead of putting more smaller ones?

 

[raisefold 10+ year member]

make your own thread..thread jacker

 

[colgatekillaa 10+ year member]

make your own thread..thread jacker

will do, sorry raisefold

 

[xluben 10+ year member]

side of the box is fine

two smaller ports is also fine

you need to calculate port displacement and subtract that from the volume.

 

[raisefold 10+ year member]

ok...I will start building a sealed box and then calculating my port length from there. The box I am making will be around 3 cubic feet...so it should give me plenty of space for the ports.

Where can I buy 22 inch long flared ports? I think partsexpress has some, but the longest is 17 inches.

 

[xluben 10+ year member]

i DEFINITELY think you should nail down your box plan before you start building.

Just to make sure, you should be using two 4" ports.

To get a longer port, just buy the flared ends and use PCV for the straight part. That's how they're designed.