Subwoofers and enclosures 101

[albysure]

if you really want to get info on anything car stereo related try the jl audio tutorials. very thorough!

http://www.jlaudio.com/tutorials/index.html

Originally posted by mxmissile
Sound quality in an infinite baffle system is EXCELLENT with the right sub -

right sub= sub with high qts

great post! Really informative and in-depth.

[Mr TransAm]

Im working on my 6 and this time i want to put 2 12"s in the trunk but i want sony xplod speakers and subs what do i have to do to get the 6x9"s to fit since the 6 have 6x8's i wouldnt think it would be that hard also are sony subs & amps ect good quality? sorry if this is on and off the subject but it origannly started about the subs and kinda branched out


thanks

[mxmissile]

Start a thread for Q's like this, it'll get a lot more attention.

6x9's can be made to fit, with a lot of work.... IMHO, not worth it, if your running an amp to them highpass, the stock speaker size will make just about as much noise, and ya' won't have to cut up your ride.

Sony blows. Cool doub;e meaning, huh?

Do a search on Sony here, you'll change your mind real quick....

My grandmother is giving me a car, a 1991 Mazda MX-6. And my sister put a new Pioneer head unit in there for me. But now I want to replace the factory speakers and put a sub in as well. I have an amp already, a MTX Thunder6304 with 4 channels. What kind of speakers and sub should I be looking for? I also don't really want to spend a fortune on them. Basically what kind of setup should I be looking for to get the best bang for my buck in my new car. Thanks.

[mxmissile]

Please start a thread in the audio forum with this question, you'll get lots of advice from everyone, including me. This thread is a box info post and box q & a, please use it as such!

[mx6rider1085]

Ok, I am making a sub box in school as a project. You guys were talking about making dure you have the right volume for the box. My box I want to cnstruct is going to be a little less than 2ft by 3ft by 14 in. This is for 2 12inch subs. This is gonna fit my trunk pretty well so i wanna make sure I have the right size because i actually have to design it. It will be a waste all that time and find out the box is not good.
Thanks

[mxmissile]

Basic geometry, man - length x width x heght, divide by 1728 (that's the number of cubic incehes in a cubic foot). You now know the approximate volume, in cubic feet, of your enclosure. You need to check the woofers info to know what size they recomend - most twelves want between 1 and 2 cubic feet sealed, between 1.5 and 3.5 ported. The box you describe around four to five cubic feet total - that's a big box! Probably some good high powered woofers and a couple ports, and it'll rip your head off.

For further info, please start a new thread, though....

[debo]

hey i was wondering i wanna put 4 12 hifonics subs in my car and wanna know would 4 12's be too much for our cars and is there a website out there that i can find my trunk size and different types of boxes that can be made only for our trunks

[mxmissile]

Again - PLEASE start a new thread with questions regarding specific box applications for specific cars or woofers.

If you search for it, it will come....

[zach_H]

One thing that wasn't mentioned that I think is relative to someone building a box is whether or not to have a divider in between a multiple sub setup.

I've read that there is much to be gained by having no divider or at least a port of some sort to connect the two chambers.

I'm curious what you have to say about this. Please correct me if I'm wrong.

[mxmissile]

Good point!

Besides the fact that a "divider" will make te box stiffer, just how important it is to have seperate chambers is a matter of some dispute. The parts of the argument that can be backed with something like real data I will put forth here.

If all your woofers are in parallel and run off the same amp, they should all be in near perfect phase with one another, thus, they may share common airspace. Some people say that sharing the airspace is benificial for SPL, I've never seen this proven per se.

If multiple subs are wired in series, they is a slight phase shift from driver to driver. They CAN share airspace, but it's beter to have them in seperate chambers. The phase shift is very slight, but if there are more than 2 subs in series, it becomes more pronounced, thus making the seperate chamber even more necessary.

When driving mulitiple woofers off multiple amps, seperate chambers are HIGHLY recomended. Unless you have an ocsilliscope to perfectly match amplifier output and phase response, sharing airspace can be very detrimental to overall performance.

That about covers it, gotta go!

My experience with bandpass, ported, and sealed enclosures are as follows:
If you want it to POUND but not quite as much audible bass, get a sealed enclosure
If you want decent pounding (movement of air) and a little more audible bass, get a ported box.
If you want a whole lot of audible bass, but not a lot of vibration, get a bandpass box.

Also, ported, nor bandpass boxes hit as low.

[brianJ]

Ok, i have read every reply so far, but, i still dont get where to find the air volume ratio thing. i am building a box to fit my 2 12's, and am putting vents and making it a slant box... are there any certain requirments, besides the air volume, that i should be aware of? Do i need to make it a 14 x 14 x 14, or what? If ya'll dont mine answering my question i would apprecitate it lots... thanks

[mxmissile]

Alright - first thing we gotta do is determine what airspace requirements and port size your subs need. Since you haven't told us what kind of subs they are, we dunno, and if you don't know I assume the subs don't come with a recomended box type or size. Please provide that info so we can help!

As to figuring volume - it was in teh initial post, but I suppose it's worth rehashing....

Multiply the internal dimensions, Length x width x heght in inches. That'll give you the total number of cubic inches in the box. If you have a slant, average the bottom and top together - if it's 30 x 14 x 16 (bottom) and 12 (top), than it's 30 x 14 x 14, for example. Now, take your final cubic inch number and divide it by 1728, the number of cubic inches in a cubic foot. You now know the total raw capacity of the box in cubic feet. Adjust the measurements as necessary to get the airspace needed for your subs, and you're finished!!

When you get us the sub type and/or box requirements, we can get into the port size and whatnot, and make box size recomendations.