Im about to begin making my sub box, I am making a ported enclosure or two (havent decide if I should just put both subs in one box or split them up) but using a bunch of programs on the net they ask for parameters from the speaker that no one seems to know like teh Z, Xmax, and Disp. Ive tried getting ahold of MB Quart but they dont want to recommend a ported enclosure size. It is recommended to use a 1.5 cu ft sealed enclosure per sub. Is there any way to figure out a good internal volume for a ported enclosure without that info, also are there general guidelines for port size. Thanks alot.

 

what subs are you using? if they are not recommending a ported box perhaps it is for a reason. not all subs perform well in ported enclosures.

 

Some subs just aren't meant for a ported box. Some subs will have the same recommendations for sealed and ported, others will have a slightly larger area for ported over sealed it all depends upon the manufacturer

 

kcid has it on that one.

 

Im puttin in 2 15 in MB Quart PWE354's, I understand that they recommend a sealed enclosure but I kinda wanted a ported I dont really like really tight bass, do you guys think sealed would still get the sub to hit the really low frequencyy's I want. thanks for input.

 

your going to be able to get a little bit more drop from oversizing the box. You can truthfully build it to spec, internally brace it with extra on the sides (figure the bracing into the displacement), double face the front and rear, resin the inside of the box, and stuff it with polyfill until you get to the sound you want.

Or you could go with a passive radiated design. Along the same lines of a ported enclosure with no port. Utilize the radiator to tune and this may be your way to the best of both worlds either or, your call, im just here trying to get a lil chicken

Radiators

also can check out the concept via google or the earthquake made slaps

 

Dragon, if the sub is recommended only for Sealed, then keep it that way. What happens sometime with subs that are meant for sealed and are put in ported box, they bottom out. Meaning that they start hitting the basket of the frame causing it to clunk. Also subs that are misused this way will not accurately produce the lower bass notes you are looking for. Keep it sealed with true steady power and probably look into a Bass Maximizer.

 

cough cough epicenter cough cough

which dochser is right on this, but utilizing a sub sonic filter he should hopefully be able to tune that out. Personally i would use the subs in the manner they are recommended or go with new subs.

You can look at
Passives for a little more info

 

I think he is looking for the more boomy low bass. I personally enjoy the tight bass, and in his circumstance I would suggest he gets the

cough cough EPICENTER cough

 

very simple...aim for a qtc of around .6 and i guarantee you that you will have sick sick low end and not very tight bass. my 10's in a .59 qtc box got much lower than my shivas did on a .9 qtc box with the same power. box size is huge for sealed enclosures trust me on this. if i had it my way id get the low end of a roughly .6 qtc sealed box with the spl of a ported box. your system may not be as loud because of the box alignment but people usually equate loudness above 50hz which is not what you are looking for. 2 15" subs sealed in a larger than spec box will produce amazing lows but remember to watch the excursion in a sealed box bigger than spec. the bigger the box, the easier the sub moves.

 

I wouldn't even look at the PR's listed on the eBay link they don't have the T/S parameters listed. It's impossible to model the enclosure properly without the parameters. Here's a link to the modeling formulas - DIY Subwoofers PR page. If you decide to go PR, then there are some quality models available from Acoustic-Visions.

I agree with slickrick on this, go for a low Qtc box. That gives you a much better roll-off on the low end. Here's a Qtc comparison - Link.

-Robert

 

Wow thanks for all the ideas, I might try what you said slickrick, if it doesnt sound as good I guess I can always try other variations.

 

no problem. a sealed box is easy to design and make, and also cheap to make with one sheet of mdf. if you dont like it, the $20 investment on mdf was worth it.

 

The 15z are going to put out boomy bass anyways. I would experiment with the polyfill, that and eq fixes should be able to get it where you want it.

 

On another note, I'm not for sure what model mb quart you are talking about but I remember Nopi Nats last year they had 2 demo vehicles both had ported boxes for their subs if I remember right and they were for the newer Quarts 2004-5 series. It was a single 4" circular port. I've had ported boxes in both set ups, one with seperated chambers and the one I have now both subs share the same chamber, the seperated chamber setup "hit" harder. Both set ups were about the same frequency.