Ok Going to be building myself a Box

[HighRev87]

I am giving my 15s one last chance, I have 2 MTX Thunder6000 15" subs. Unfortunatly I never recieved the pounding I wanted out of them. Many have told me to go ported, and that the sealed box wasnt even built to the right size anyway. I have also been told that my amp isnt good enough for them. So I am going to upgrade the amp and build a new box.

I am going to be using 3/4inch MDF. I have a book that helps with the basics on building a box (it is actually an all car-audio book) so I have the BASICS down. However I was wondering if thier is anything else I should know before I start. Any tips greatly, and I mean greatly, appreciated.

Also Do you know any good sources to order the carpeting and/or port tubes? If so hook me up.

Thanks,
HighRev87

[CocaColaEatsPie]

One thing that I learned the hard way is to drill out the holes before putting the screws in, it is very time consuming but I will deffinently be doing it on my next box

Don't over do the screws. You only need 2 for each side, maybe 3 if its more than 3 feet long. The glue is the primary bonding matterial. Believe it or not it is actually stronger than the wood once dry.

Clamps make the project much easier, a corner clamp and a long clamp.

For ports I used PVC pipe because you have to make it the right length for your tuning frequenzy. Just be careful to cut the whole to put the port in as close as you can to the size of the pipe. It's hard to make up for it if you cut them too big.

Carpet can be found cheap at www.partsexpress.com.

Good Luck

[alesserfate]

i made my own ported boxes and they kick ass....

make sure your amplifier mathes the impediance (ie. 4ohm amp for a 4ohm sub) and amps RMS power output is just a bit higher then ur subs (300RMS sub, 350RMS amp) and that the peak power output on the amp is also just a bit higher then the subs.

for 4/3MDF u should use a screw about every 5-6 inches, use a 2 inch long screw, pre drill holes, use silicone waterproof bond for where the sides meet, there is a sheet that comes with ur subwoofer, that states the xmax, power, box volume, etc, in that book of urs should be a math equation that tells u to sub in the xmax and the box volume and then it tells u what port diameter u should make and how deep the tube should go in the port

plus u can find some software download online for free regarding the boxes design and ports and all.. if u encounter a program that helps u calculate the Hz, remeber, the lower the Hz, the deeper ur bass will be.

ported always ssounds louder then sealed, even though sealed has lower Hz, u often cant hear it cause its too quiet, so u'd rather have a louder 30Hz bottom end than a quieter 27Hz....

hope i helped yah... cya

[Brandish]

Well first off I'd reccommend checking to make sure you have enough room for two 15s in a ported enclosure. MTX reccommends at least 3.00ft^3 per sub for a tuning of 40Hz per sub, so already you're dealing with at least 6ft^3 internal volume, plus sub displacement, plus port displacement, and that's internal volume, so remember the thickness of the wood will make the outside dimensions bigger.

Secondly - and this is totally your decision - but I've found that using a slot port rather than round is much better for a few reasons... For one, it's usually reccommended that the ports be on the same plane as the sub to avoid cancellation issues. In order to get enough port area so that you're not getting an arseload of noise, you're either going to need one big-ass port (at least 4" I'd say), or mutiple smaller ones. This is going to take up a lot of space on the box, and you're pretty limited with placement. Having a slot port will allow you to get lots of port area, and the dimensions are very flexible... You could make the port 2.5" high and have the length run the entire box so you're maximizing space better. I find slot ports easier to work with also, especially when you're dealing with lengths that require you to put a bend in the port. It's much easier to do that with wood than with PVC, however you can get PVC with 90 degree bends if necessary. Lastly, you can utilize one complete side of the box for the port, so say your slot runs the entire height of the box, you only need to build one piece of the proper length for the port. But anyways, like I said, that's totally your preference.

Most lumber places will cut the wood for you on their $100,000 panel saws. They're usually pretty accurate, but it depends on the person using it and how busy they are. If you have a table saw, it's probably better to make most of the cuts yourself (assuming you're good at measuring ) I normally use 1 1/2" double-threaded floor screws to screw the box together, and any carpenter's glue is fine. Construction adhesive is apparently stronger, but it's really messy and takes longer to cure. Always pre-drill your holes, especially when using MDF. Take care in placement of the holes because MDF splits easily. Always work on a flat surface so you can flush your edges up nicely. Try to use a router for the mouting holes for the subs, but if you don't have one a jigsaw is fine, but not as accurate. Oh, and if you're planning on carpeting the box, it's a good idea to recess a couple of the sides so you can hide the seams easier. That's all I can think of for now...

[Brandish]

Originally Posted by alesserfate

i made my own ported boxes and they kick ass....

make sure your amplifier mathes the impediance (ie. 4ohm amp for a 4ohm sub) and amps RMS power output is just a bit higher then ur subs (300RMS sub, 350RMS amp) and that the peak power output on the amp is also just a bit higher then the subs.

for 4/3MDF u should use a screw about every 5-6 inches, use a 2 inch long screw, pre drill holes, use silicone waterproof bond for where the sides meet, there is a sheet that comes with ur subwoofer, that states the xmax, power, box volume, etc, in that book of urs should be a math equation that tells u to sub in the xmax and the box volume and then it tells u what port diameter u should make and how deep the tube should go in the port

plus u can find some software download online for free regarding the boxes design and ports and all.. if u encounter a program that helps u calculate the Hz, remeber, the lower the Hz, the deeper ur bass will be.

ported always ssounds louder then sealed, even though sealed has lower Hz, u often cant hear it cause its too quiet, so u'd rather have a louder 30Hz bottom end than a quieter 27Hz....

hope i helped yah... cya

Woops... Forgot about the silicone. Good call.

[HighRev87]

Brandish, If I were to give you the specs for my max size box, would you be able to hook me up with plans? Or anyone else here. I do think that the slotted ports would be alot easier, but probally take up more room.

BTW Thanks for help all

[CocaColaEatsPie]

what kind of car is it going in?

[HighRev87]

Well anywhere from now to a month from now I will be buying a Mustang GT. I hear they have small trunks so im not sure if it will work anymore.

A freind of mine has a Ford Explorer XLT and he had 2 12's Fosgate Stage 1 in his trunk....huge ported box. However It took away his ability to use a third row seat, so when he upgraded the subs to 2 fosgate stage 3s, he told his guy to build the box small so it would fit behind his third row seat. The guy did it. The box looks so small and is supposably stuffed with that poly-fill stuff. I thought he would lose sound from the box, but they still pound hard. So I am thinking maybe Ill just bring it to that guy. See what he can do. He can probally also hook me up with a new amp.

[Brandish]

Originally Posted by HighRev87

Well anywhere from now to a month from now I will be buying a Mustang GT. I hear they have small trunks so im not sure if it will work anymore.

Two ported fifteens in the trunk of a Mustang?

You'd have to build the box inside the trunk...

[HighRev87]

Yea I began to realize it is less and less of a possibility. Im thinking I will call up the guy who did the box for my freind. If he doesnt think he can pull of a similar box style, then im going to be forced to sell them and get 12s. I have a hook up through circuit city for infiniti subs/amps, so ill look into that more if he cant do the box.

[CBFryman]

Sloted ports are the way to go....easyer to change the tuneing, harder to make than just drilling a massive hole and then sliding a pre tuned plastic tube in though....any ways pre drill holes, seal with olts of silicon and make sure to dampen the inside of the box...oh ya and use lots of bracing...corner braces and internal braces (if possible) really help keep the box from resonating....two ways of dampening that i like are (and can be used togather) are to spray the inside of the box with a rubber coating (Make sure to calculate extra volume into the box if yo uare going to use this as your primary dampening because it will have to be layed on thick) this rubber coating not only helps absorb sound and vibrations but also assures you that you have a good seal. dynamat is the most often used but i prefer that spray in truck bed liner stuff because it is cheaper. the other is poly fill...like the stuff in pillows...fiber glass insulation can also be used but is a pain to work with...the fiber fill absorbs large amouns of vibration but allows for sound waves to pass through....just make sure to have a clear path way from the back of the cone to the port as to not get the port cloged becausethat would heighten port noise and in extreme cases clog the port partially....

[CBFryman]

oh ya and make sure to let the silicon cure for at least 24 hours before droping the woofer in as the vapors released fro mthe drying silicon may hurt the cone/suspension of the woofer...