Port area : do I have enough for my Icon 15?

[Notorious97200 339]

Hi,

I've read everywhere I could, but I get very different informations!!!

My enclosure is about 4 ft3 and has a round 5.6"(diameter) PVC port; port length is 14".

It sounds good, but I 've read that port area should be much bigger : 4 (ft3) * 15 = 60 sq inches. And my port is far from that.

I don't really know the actual tuning, but I would like it to be around 30-32 hz.

Do I have enough port area ? Or enough length? Enough port ?

Please, help me !!!

[poundindak69 15]

right now i got its tuned to about 30hz but i think you need a little more port area

[KU40 173]

Yeah, you only have about half the port area I'd recommend for that sub in that enclosure. You have about 24.5 sq. inches.

[Notorious97200 339]

Yeah, you only have about half the port area I'd recommend for that sub in that enclosure. You have about 24.5 sq. inches.

So, what to do ? Add another port with the same area, but how long?

Or replace the port with a bigger one? I have a 8" diameter pvc tube, can I use it? How long should it be?

Last question : what will be the benefits of having a bigger port area? More output, I hope?!!!

Thank you for your answers!

I am waiting for them.

[KU40 173]

You may increase output, but it wouldn't be noticeable, and that's only if the port is stifling the sub, which you may have enough to avoid that. About the only real problem with that amount of port area is if you have port noise (chuffing).

If you have port noise at higher volume, you can either add another or use the 8" port as you said. If you add another 5.6" port, they would each need to be about 40" long, but it would cut your enclosure volume down to about 3.1 cubes. If you went with the 8" port, it would need to be about the same length and you'd see the same drop in enclosure volume. Two 5.6" ports have 49 sq. inches, one 8" port has 50 sq. inches of area. That's a bit long, I know. That's for a 30 hz tune. You could raise the tune to 32 hz and each port would need to be 35 sq. inches and your box would be about 3.2 cubes. Not much difference there.

But if you don't have port noise now, you're probably fine and don't need to change.

[Notorious97200 339]

40" long??? How can I do that? External port?

Maybe I am completly wrong in conversions between inches, centimetres,...?

No, no, I know 1 inch = 2.5 cm!!!

So ?

I must admit my bass is hitting hard and sound good too!!! But I just want to learn and improve what I have if possible.

You, at SSA forums have more knowledge than what I can find in my country!!! And you don't mind "teaching" the people.

Thank you

[KU40 173]

You can do an external port, but that would change my suggestions since you would no longer be displacing the air inside the box. So we'd have to come up with new lengths for you. But as far as inside the box, if you can find some 90 degree corners, you can just put those on the end of one port piece, then run the port along in a different direction inside the box. It doesn't have to be straight.

But if you are having no noise problems now, I wouldn't worry about it.

[Notorious97200 339]

Thank you for your advice, but I think 40" will be way too long for my box!!

I will keep what I already got.

If I upgrade next year with an Xcon 15 I will build another box!!!!!!!!!!!!!!!!

I like my sub more and more. I couldn't believe it would slam like that with only 650 w rms.

As I can't change my amp now (money is short ) , I wanted to improve the box. Maybe it is good enough!

I thought that a bigger port area will make me shorten the port, but I was absolutely wrong. Hopefully I didn't make the change before asking here.

So, thank again.

[KU40 173]

Yep, unfortunately larger port area means the port has to be longer for the same tune.