Dunno if this should go in the auto section, but I figured I'd get more traffic here. I know I've read posts in the past from guys who know a lot about subs and what not, so here's my question, I just ordered 2 Infinity Kappa Perfect VQ 12"s that I'm gonna run with an Infinity 1211a amp. Me and a friend are gonna make my own box, and I was curious as to what specifications I should build it to. I've searched around, Google and all, and the only thing that helped was the Infinty website, although it hadn't been updated yet to include the VQ on the Boxes and Parameters section. Preferably I'd like a ported box, and any help with this would be greatly appreciated. Thanks

You'll blow your hearing out and piss off your fellow motorists.

Need to know the stas on the speakers before anyone can tell you anything on what size/volume th ebox needs to be. And the vehicle its going in. Power of amp?

I have built a squawker and a tweeter but never a woofer.

though it plays a part, the dimensions of the box are not that big of a deal.  The only think to consider is smaller boxes should be sealed, and larger boxes should be ported.  you should also seal the two speakers off from eachother, regardless if the box is ported or not.

adjust the box size to the area you want to install it in.  the manual for the speakers should give you an idea what kind of cubic inches you want for the size of the box.

The amp is 1200 watt class D amp. mono channel 1300W x 1. And they're going in a Nissan Xterra.

you would probably be better off asking this question on sounddomain.com
FWIW I have 4 18" subs in a sealed box in one of my blazers......

I have a single 15" sub in a sealed box in my other blazer and I have a single 10" sub thats in a ported bandpass enclosure in my little Canyon. And I really could care less about bugging the people who are in the lanes next to me.

Quoted: though it plays a part, the dimensions of the box are not that big of a deal.  The only think to consider is smaller boxes should be sealed, and larger boxes should be ported.  you should also seal the two speakers off from eachother, regardless if the box is ported or not. adjust the box size to the area you want to install it in.  the manual for the speakers should give you an idea what kind of cubic inches you want for the size of the box.

What the fuck did you just say??

First off, the box is the MOST important part of the subwoofer system. More important then the type of sub, more important then the amp. You can make a crappy sub sound good or make an excellent sub sound like trash all based on how good of a box you built.

Also, there is no hard and fast rule as to large ported or small sealed. Its all what you want to accomplish. Small ported and large sealed boxes do exist, they have there purposes.

Also, it doesnt matter if the subs are sealed from each other or not. It makes no difference, in fact in a passive radiator system you have to have all subs share the same space.



Having said that, I'd suggest one of two things. First is follow the manufacturers directions. They generally have some box specs in the info that came with the speaker. You could follow that and have a decent box.
Second, if you want to get all out download WinISD Pro (Google it, its by Linear Team) and model your exact box using the speakers you have. This will tell you exactly what your getting. Sealed boxes are easy. ported boxes, try to keep your tuning point above the F3 of your sub and make sure you check for port velocity and keep it under roughly 60 ft per second, although you can go up to around 100 or more if you design a flared port.

I use a program called WinISD to design my boxes.  You can download it free off the net.  You'll need the thiele small parameters from the owners manual or just e-mail the manufacturer.  You can adjust the dimensions of your box to fit your application using WinISD.  Like somebody else here said, you'll want separate airspace for each woofer.  Make the box out of 3/4 inch MDF and seal all the cracks with silicone.

Quoted: you would probably be better off asking this question on sounddomain.com FWIW I have 4 18" subs in a sealed box in one of my blazers...... I have a single 15" sub in a sealed box in my other blazer and I have a single 10" sub thats in a ported bandpass enclosure in my little Canyon. And I really could care less about bugging the people who are in the lanes next to me.

carsound.com > sounddomain.com.

Although man, the off topic section of SD is alot of fun. I dont know how many times I've been banned....

Quoted: Quoted: though it plays a part, the dimensions of the box are not that big of a deal.  The only think to consider is smaller boxes should be sealed, and larger boxes should be ported.  you should also seal the two speakers off from eachother, regardless if the box is ported or not. adjust the box size to the area you want to install it in.  the manual for the speakers should give you an idea what kind of cubic inches you want for the size of the box. What the fuck did you just say?? First off, the box is the MOST important part of the subwoofer system. More important then the type of sub, more important then the amp. You can make a crappy sub sound good or make an excellent sub sound like trash all based on how good of a box you built. Also, there is no hard and fast rule as to large ported or small sealed. Its all what you want to accomplish. Small ported and large sealed boxes do exist, they have there purposes. Also, it doesnt matter if the subs are sealed from each other or not. It makes no difference, in fact in a passive radiator system you have to have all subs share the same space. Having said that, I'd suggest one of two things. First is follow the manufacturers directions. They generally have some box specs in the info that came with the speaker. You could follow that and have a decent box. Second, if you want to get all out download WinISD Pro (Google it, its by Linear Team) and model your exact box using the speakers you have. This will tell you exactly what your getting. Sealed boxes are easy. ported boxes, try to keep your tuning point above the F3 of your sub and make sure you check for port velocity and keep it under roughly 60 ft per second, although you can go up to around 100 or more if you design a flared port.

Exactly. The box IS the subwoofer system...for the most part. Going sealed or ported depends on a number of things. With most subs, the recommended sealed box is almost always smaller than the ported alternative.

Considering you're putting this in something fairly large, you have the room for a ported box, but with 2 12" wooofers, a ported box is more than likely going to take up most of your room. If you don't care about that, than no big deal. Also, 12" woofers usually require nearly twice the space as 10" woofers and 10's require nearly twice as much as 8" woofers.

Usually it's best to determine how much room you have or willing to sacrifice before determining which subwoofer to go with.

Sealed systems are more forgiving with design errors than a ported box, so in your case, sealed might just be better. They're easier to build and they take up less room...generally. I don't know the specs on those exact subs, but they probably need somewhere around1-1.5 cubic feet of air space per woofer. The ported box is probably 50% larger. Also, don't worry about putting them in the same air space as long as you plan to run them mono. Stereo subs are a diffeent story though.

Quoted: Exactly. The box IS the subwoofer system...for the most part. Going sealed or ported depends on a number of things. With most subs, the recommended sealed box is almost always smaller than the ported alternative. Considering you're putting this in something fairly large, you have the room for a ported box, but with 2 12" wooofers, a ported box is more than likely going to take up most of your room. If you don't care about that, than no big deal. Also, 12" woofers usually require nearly twice the space as 10" woofers and 10's require nearly twice as much as 8" woofers. Usually it's best to determine how much room you have or willing to sacrifice before determining which subwoofer to go with. Sealed systems are more forgiving with design errors than a ported box, so in your case, sealed might just be better. They're easier to build and they take up less room...generally. I don't know the specs on those exact subs, but they probably need somewhere around1-1.5 cubic feet of air space per woofer. The ported box is probably 50% larger. Also, don't worry about putting them in the same air space as long as you plan to run them mono. Stereo subs are a diffeent story though.

And once you factor in cabin gain for a large vehicle, it could end up being a bit boomy down low. Sealed boxes are really forgiving. I mean a blind guy could make one. Ported boxes, while you can be sloppy, even a small error can have quite a change from what the intended design was.

As for stereo...Who runs subs stereo? I've never heard of that. Not to say it hasnt been done, but subs are almost always mono.

Quoted: Quoted: Exactly. The box IS the subwoofer system...for the most part. Going sealed or ported depends on a number of things. With most subs, the recommended sealed box is almost always smaller than the ported alternative. Considering you're putting this in something fairly large, you have the room for a ported box, but with 2 12" wooofers, a ported box is more than likely going to take up most of your room. If you don't care about that, than no big deal. Also, 12" woofers usually require nearly twice the space as 10" woofers and 10's require nearly twice as much as 8" woofers. Usually it's best to determine how much room you have or willing to sacrifice before determining which subwoofer to go with. Sealed systems are more forgiving with design errors than a ported box, so in your case, sealed might just be better. They're easier to build and they take up less room...generally. I don't know the specs on those exact subs, but they probably need somewhere around1-1.5 cubic feet of air space per woofer. The ported box is probably 50% larger. Also, don't worry about putting them in the same air space as long as you plan to run them mono. Stereo subs are a diffeent story though. And once you factor in cabin gain for a large vehicle, it could end up being a bit boomy down low. Sealed boxes are really forgiving. I mean a blind guy could make one. Ported boxes, while you can be sloppy, even a small error can have quite a change from what the intended design was. As for stereo...Who runs subs stereo? I've never heard of that. Not to say it hasnt been done, but subs are almost always mono.

No, most people don't. I was just putting that out there for clarification purposes. It's possible if you didn't have a mono amp, a bridgeable amp, or just ran them in stereo off of a stereo amp.  I run my 2 JL Audio 10''s in mono like most people do.