Would I gain from a larger port?

[7ender 10+ year member]

Currently, i'm running a BTL in a 4 cube box at 33hz.

It's loud, but i'm wondering if I could gain some spl by putting in a larger port. It currently has a 6" flared aero (which equates to 28 square inches of port area, or a ratio of about 7" of port per cubic foot). I realize this probably isn't enough area, the box was originally made for a lower powered sub.

I'm also underpowering the BTL a bit, it's off 1600. Normally i'd just try this out to find out for myself, but it's going to require quite a bit of work as i'm going to have to fabricate a 7" aero.

So for those that have experience with similar setups/aero's- do you think i'd notice a gain upping the port area? A 7" aero will yeild about 39" of port and a ratio of ~9" per cube.

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[SSS 18734 5,000+ posts]

You'd be more likely to gain SPL if you tuned higher, made the box a bit bigger, or gave it more power.

 

[7ender 10+ year member]

Yeah, I know. But unfortunately those pretty out of the question. No money for more power, no space for a bigger box, and I like my musical btl (yes, I know...).

 

[AllDayMJ 10+ year member]

Yeah, I know. But unfortunately those pretty out of the question. No money for more power, no space for a bigger box, and I like my musical btl (yes, I know...).

go bigger, easiest and cheapest way to gain SPL, you can easily run 12sq.in. of port per cube and be very musical. id try that if i were you. shoot for about 40sq.in. ish

 

[SSS 18734 5,000+ posts]

If you can't go any bigger, then a bigger port is just going to raise your tuning... unless you can make it significantly longer. But that, in turn, will eat up your internal airspace.

 

[AllDayMJ 10+ year member]

bah, lagging hard. bump for 2x poast

 

[7ender 10+ year member]

Think it'll be a noticeable difference moving from 28 to 39" of port? And no, I wouldn't lose any volume...if I do the larger port, it'll be going external.

 

[AllDayMJ 10+ year member]

yea, response will change quite a bit, i noticed from 42 to 60 a huuuge difference, from my experience at least..

 

[7ender 10+ year member]

Hmm. Havent' needed any larger than 6" aero's before...any recommendation on how to make a 7"? I know you can use sonotube, but I don't want an 8" port //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif.

 

[etznova 10+ year member]

Bigger is not always better, but then again......

I run a Dd 9515 in 4.25 cubes with one 6" areo. With two 6" areos the sub was very sloppy and distorted very at about mid volume which was quite a bit lower in volume compared to a single 6".

Of now heres the kicker my brother same sub about the same size box but different vehical uses 2 6" areos and it works out great. His car is a honda CRV mine is an ext. cab. sonoma.

So you'll just have to try it. and see

 

[shizzzon 10+ year member]

in my testing, increasing port area will raise pressure level higher than properly tuning to your car's peak frequency.

I know this isn't for comp but to answer your curiosity, it would be better to increase your port area rather than increasing tuning.

For daily- it's advisable to do 12-16sqin per cube.

For comp - 28-32sqin per cube.

 

[SomeGuyDude 10+ year member]

I forget the exact science behind it, but doesn't adding a little fiberglass insulation sort of have the same effect as increasing the volume of the box? Might be a possible solution if space is an issue. Unless I'm totally off-base, in which case disregard.

 

[7ender 10+ year member]

You're referring to polyfill...which is usually used in sealed boxes.

As for the 12-16 rule, I usually refer to that but iv'e found that for aero's I can get away with less (sometimes as little as half). Think i'll try a 7" port this time.

 

[skmfkr 5,000+ posts]

12-16 is for slots.

i like 10 per for aeros