vk_308

hi
after some help regarding sub boxes. i have 2 12inch lightning audio subs 1500watt max and 500 watt rms each. im mainly after SQ wuth loud deep bass. should i use a ported box. il have the subs facing backwords with the port either going thru the rear seat where the arm rest comes down or thru the parcel shelf above. how big does the box be. how many ports, bow big and long is the port(S) have to be. have one big box or 2single. this is a large sedan(holden commo)form australia any suggestions would be greatly appreciated cheers

Pipes

sounds like dukk has brainwashed you
deep bass and good SQ sounds like a sealed box to me. unless you intend to tune the ported box really low, but then you might end up with a weird freq response

vk_308

cheers for that. what size should the sealed box be for them? and any hints on shape and building it?

maltesechicken

I hate it that so many people say that sealed are for SQ and ported for SPL. If you know how to build it, ported is best for SQ and SPL.
When you seal a box, it will give you a more gradual frequency roll off and will extend lower. However, the rolloff typically starts around 80-100hz. With ported, if you do it right, you can prevent any roll-off from happening until 30-40hz giving you a more accurate sound reproduction and a deeper, fuller low end. Just with a ported set up, the roll off is much steeper when it happens. But when the roll off starts at 30 hz, it doesn't matter because hardly any music plays that low.

For SQ, go ported.
If you think ported is only for SPL, you haven't yet heard a well built SQ box.
My $0.02

maltesechicken

VK_308

Have you come up with a box design yet?
I still strongly recommend ported, but it has to be done right.

If you have the thiele Small parameter for the sub (QES, QMS, QTS, BL, FS, VAS, Xmax, LE etc) post them and I am sure there are a few people around here who can give you a hand.