Porting a subwoofer box?

[Hair]

I'm totally stupid when it comes to stereo stuff, so help me out here please.

I thought that porting was something that you did to a subwoofer box when you couldn't make the box big enough for the required cubic feet needed, so then you made it as big as possible and then ported it. Is that even close to being right?

So what is the reason for a port in the first place?

Are ported boxes better than sealed ones?

When do you need to port a box?

What size ports do you make?

How should a port be made... just a hole in the side of the box??

As I look at woofers in the catalogs they say like 1 to 3 cubic feet required... well what is it... 1 or 3?? One size has to be better than the other.

I know these are probably basic questions for you "system" guys. Please help.

[AceX]

Ported boxes are awesome provided you can get them to work right. They take alot of engineering and calculation to construct properly.

A ported set-up is generally used to increase SPL and is better than a sealed box for this application. I prefer sealed boxes for SQ set-ups, but have seen ported boxes work very well.

A port's size depends on the sub that is feeding it with air. A port is used to make use of the return thrust of the sub woofer, in theory doubling the output of the woofer. You have to take into account the air that the sub needs, the max excursion, the port's displacement, magnet displacement, bracing displacement, and air flow.

It's a very complicated process for sure. On top of all this, the port size and length will determine how the sub sounds.

try these links:

http://www.crutchfield.com/learn/lea..._building.html

http://www.crutchfield.com/learn/lea...nclosures.html

[Hair]

What does "SPL" and "SQ" mean?
Is that box in the back of your truck that's in your picture and all over the forum ported?

[tommyd241]

Originally Posted by Hair

What does "SPL" and "SQ" mean?
Is that box in the back of your truck that's in your picture and all over the forum ported?

SPL=Sound Pressure Level. SQ=Sound Quality.

Many factors are involved in porting a box correctly. They can be ported using tubes or created by building the ports into the box. WinISD is one program audio heads use to design custom boxes.

If you give me the specs of the subwoofers, the dimensions of the available space, what kind of music you listen to, and what you want as far as sound is concerned (e.g. loud, deep, low, tight, bass)... I can ask somone on www.icixsound.com to design a box for you or you can register there and ask them yourself.

[AceX]

No, my box is not ported. There really isn't enough room behind the seat to port the box, especially for my application.

[frostie_122]

ported boxes are bigger...ususlly 1/3 bigger give or take.
depending on the sub porting might increase or decrease sound quality.
we sell JL Audio and a w7 in a ported box i think sounds just as good as a sealed box but will also hit lower frequency's.

a slot port will sound ten times better than cutting a hole and putting a flanged port kit in.

when a spec sheet says 1-3 cube that's where you can minipulate the subs sound how you choose. 1 cube and it will be tight and not hit as low. 3 cube and it will be boomier and hit a little lower.

ported enclosures also dont need as much power to run the sub.

porting is an awesome way to get more output and not having to double your power or double your power...ie dont have the funds for 2 12" subs and a big amp to run it? Buy a 12" sub and build a ported box and an amp with half the power. it will be close to the same output...close.

and last bit of information...DO NOT BUY A PREMADE PORTED BOX UNLESS ITS SPECIFIC FOR THE SUB. EVERY SUB DIFFERS IN AIRSPACE FOR PORTING REQUIREMENTS.

[frostie_122]

...and most subs dont have a range that big in air space requirements, 1-3 cube. usualy .5 or .25 difference.