ported box.

[2MPRS]

hey guys im thinking of building a bigger sub box(ported) just wondering how hard it would be to build my own? is it worth it or should i get one built from a pro?

[arverson]

any specific reason/s for wanting a ported box?

got the t/s specs of your subwoofer/s?

is this for a daily car or are you competing in db drag racing and wanting to get every single decibel possible for those few seconds of burps before you fry your sub/s?

reason i ask is because if its a daily then a sealed box will/should go plenty loud enough for you. depending on sub, box & car environment, lets say your optimum sealed box will get you 120-130+ db. going ported will give u a gain of very few decibels.. and those extra few decibels wont matter unless you plan to pump your sub to MAX volume EVERY single second your driving. sure the ported may play a little lower (say for example 20-30hz) but in a daily system, the majority of music dont have much below 40-50-60hz so its pointless. basically in a daily/sq setup the theoretical gains are too negligible to even worry or care about. if you care about playing that low, loudly, efficiently than id say get a better sub that can do so cleanly & reliably in a sealed enclosure. and an amp with more juice

now if your in spl racing, but still have to ask about how to build one, then id say let a pro build it cus its a little more complicated to build and easily get wrong compared to sealed.

its all about compromises & priorities. sorry about a essay but its gotta be asked if you want the best answer

:)

[2MPRS]

ahahahah thanks for all the info very helpfull. the only reason i wanted to build one is cause my sub box is a bit worn so ill be getting a new one anyway. i have an option audio amp that runs 300rms @ 4ohms and 2 jbl gt5 12's. on the jbl site is wants 49.55litres for a vented box per sub and 28.32litres for a sealed box. ive always run sealed boxes but ive been told these subs run better ported and ported would be better for the type of music i listen to.

btw rep'd for ur help

[arverson]

what do you mean by a worn sub box?

i rarely go by the manufacturers recommended volume as theyre far from ideal.. instead i use the t/s specs (namely the fs, qts & vas) so if you can provide those i can model those specs in a program & come up with a more optimum box for ya.

your type of music doesnt really play a part cus like i said the majority of music dont play much or even have anything below 40-50-60ish hz. you'd basically be chasing benefits that aernt there.

its up to you tho. theres plenty of pros who can build ya a ported box if you really want it.

[2MPRS]

its a crap box and sub combo for ages ago got a crack in it not worth using again. ported boxes look hard to build lol might just build a sealed one or get built as they are alot smaller in size. heres the spec sheet i think this is what u want again thanks for ur help http://www.jbl.com/resources/Brands/jbl/Products/ProductRelatedDocuments/en-US/BoxesandParameters/GT512Tech_050108.pdf

[slimx]

make a sealed box and buy a big drill tip :D lol

[2MPRS]

slim id be better off just sticking the subs in the parcel shelf btw im taxing ur splits while ur gone lol

[arverson]

ok modeled the specs

dunno what box you have your twin subs in atm but a 56L (28L reccomended size x 2) is too small. you'd actually be choking them of the lower frequencies.

an optimum sealed box for these subs would be about 80-112L. thing is thats a big box & i dunno how much space you're willing to give up.

to be honest what id do is get a better sub, that can play louder & lower in a smaller box, but thatll cost..

cant expect entry-level subs to have the performance of a 500-1000+ sub

guess you now have to think about compromises & priorites, see if you wanna work around what you have or sell em & get something better.

[2MPRS]

i never use my boot anyway lolz soz gonna go ahead with building the box tyvm for ur help

[arverson]

no probs

but seriously 80-112L is gonna be massive box. i know you said you dont use your boot but alternatively you can use just one sub in a 50ish L box which is a little more practical. (depending on amp load/subs voice coils configuration).

[tylerjames]

I'd seriously consider getting a pre-built box designed for your subs.
I built a split ported box for my 2x 1200w JVC subs.

Only because I had a spare weekend, and all the materials available to me.
did everything right, with the materials and seals, had it built to the mm to fit snug in my boot
but I can definitely tell the difference from my box and others that I've had previously as well as mates.

By all means it still sounds awesome, and does the job hands down. (plus looks good).
but, if you want to take it really seriously, I'd look at buying factory boxes or getting professionals to help out.

:)

[2MPRS]

ended up building a sealed 100litre box with different subs. 137db with 410rms to each sub and sounds really really good