Huge delima

[KU40 173]

OK, hold on, this is all getting confusing. Start over. List the dimensions of the box and what you want to do with the port and what limitations you have with where you put it.

[Ryan horn 0]

OK, hold on, this is all getting confusing. Start over. List the dimensions of the box and what you want to do with the port and what limitations you have with where you put it.

okay the box is currently 29x10x16. And it had a 3x9 round port and I just put in a 4x12 yesterday it sounds better as far as port noise and sq but now won't hit low notes. But really my only limitations are the lengh of the port. Someone posted I need two 4x30 round ports and the max length of port I can get is prob 14 inchs. So to get everything tuned right and proper ports I am willing to build a new box to get the right cubic feet. I just need to know how to tune it...

[Don Ganso 13]

You know the port tuning equation right?

Port Length= ((8466.4 x radius^2)/(Boxvolumecuft x Frequency^2))-(1.463 x Radius)

Also, why is 14 inches your max port length?

[Ryan horn 0]

You know the port tuning equation right?

Port Length= ((8466.4 x radius^2)/(Boxvolumecuft x Frequency^2))-(1.463 x Radius)

Also, why is 14 inches your max port length?

thank ya for the equation but that is my max bc I can't bring the port down from the top and to wedge it through the sub hole it can't really be any longer. From trunk floor to the top deck is only like 18 inches and I am porting though the deck to prevent trunk rattel

[KU40 173]

So you are totally against having any of the port inside the box?

[Ryan horn 0]

So you are totally against having any of the port inside the box?

No that's not what I meant... What I'm saying is the the clearence btw the top of the box and the truck deck (the area behind the bak seat and bak window) is only about 8 inches so I will have to have most the port inside the box or do mulitiple ports to keep the ports ouside of the box.

[KU40 173]

You know that you can bend the port, right? Put some 90* angles in there and turn it to run wherever you want it to.

Is your sub firing backwards with the port up right now? That might be your problem. Subs normally work better if you can load them off of a surface, like the rear bumper. If you can, try pushing the box to the back of the trunk and have it only a couple inches from the bumper with the sub firing backwards.

What if you scrapped the idea of porting through the rear deck and just did a backwards-firing setup? Otherwise, if you want to port through the rear deck, I'd recommend sealing the trunk off behind the box and firing the sub forward, because right now what you basically have is the port sending sound one way and the sub sending sound a completely different way and into two separate chambers (trunk for the sub, cabin for the port).

[Ryan horn 0]

You know that you can bend the port, right? Put some 90* angles in there and turn it to run wherever you want it to.

Is your sub firing backwards with the port up right now? That might be your problem. Subs normally work better if you can load them off of a surface, like the rear bumper. If you can, try pushing the box to the back of the trunk and have it only a couple inches from the bumper with the sub firing backwards.

What if you scrapped the idea of porting through the rear deck and just did a backwards-firing setup? Otherwise, if you want to port through the rear deck, I'd recommend sealing the trunk off behind the box and firing the sub forward, because right now what you basically have is the port sending sound one way and the sub sending sound a completely different way and into two separate chambers (trunk for the sub, cabin for the port).

no i wasnt sure if i could turn it wit out messing with the sound but i cant turn it either lol. the box is only 10 inches deep with the sub in the middle which is 8 inches deep lol. but no the sub is firing forward. i have had the sub firing backward and it sounded amazing i just had to lay my seats down all the time which is a big inconvience. and the box is sealed off from the trunk like u are talking which helped sound now i just wanna get my port right.

so i did some research and found some calculators on the internet that tell me a 3 inch port with 2.4 cuft needs to be 29 inches long. so now my question is if i do two 3 inch ports which is close to the recomended vent area should i make each one 14.5 inches long or does a muti port mess with sound?

[KU40 173]

No, multiple ports is fine. Many people do it. But unfortunately ports don't work the way you envision. The tuning frequency isn't dependent on volume of the port, it's the relationship of port area to port length. You're not going to like me when I say this, but if you add another 3" port, each port actually has to be longer.

Here's what I would suggest. Get yourself a 4" aeroport. If you're really scrapped for space, you might be able to get away with it. I think they arrive at 16"? Anyways, leave it as long as you can and plug it into the box. A 4" port at 16" long would leave you approximately 1.7 cubes tuned to 32 hz. That's about the best you can do to keep the internal volume as high as possible while having a chance that you won't have port noise (although you still may).

How did you get a 2.4 cube box? According to my calculations with the dimensions you described as being the outside dimensions and assuming 3/4" wood, you have 1.9 net volume inside the box.