whats going on im on the planning stage for building a custom box for my 90 camaro. the box will consist of 2 12 rockfords, 2 mtx thunder amps(200 watts each) a capacitor and a distribution cap, and maby some neon lights. i have a couple of technical questions that i hope some of you will answer.
1. do you have to have a certain amount of space between the magnet and the box
2. is there a certain angle that i should have the subs facing eachother, they are going to be indirect, sort of pushed back into the corners facing forward, but toward the other side of the car
3. can would have the box open for both the subs or do they have sealed from eachother(note each sub has its own amp)
4 when amps are beneith plexi-glass do they have to have a fan
i guess that just about covers it, thanks for all those who reply

 

1: Some subs vent through their magnet (you'll see a hole in the center) which allows them to cool, so you probably want to allow room for the vent. Also you probably don't want the magnet touching the box, or it may vibrate. Other than these things, you should be alright.

2: Doesn't really matter. If I pictured correctly what you were describing, you should be alright.

3: While it is not imperative, there are numerous benifits to having each sub seperatly sealed, especially if you are running seperate amps.

4: It depends on how hot the amps run, and how hard you push them. It would probably be a good idea to use fan(s), althought I have heard of people not using fans and being alright. At least make sure they can vent, but I would probably use fans.

Hope this helps.

- Mike

 

Nothing too different from what Mike said, but maybe a couple small additions.

1. Most subs vent their pole-piece through the magnet. Even if it's close to the box it will vent well enough, but I've seen a lot of subs actually create "port noise" which is quite audible through the cone under high excursion. It causes back pressure behind the dust cap and causes the cone to flutter which causes the sound. Keep a couple inches of space if at all possible.

2. Their orientation doesn't matter.

3. When you run 2 separate amps, you should ALWAYS put the subs in separate chambers. Unless you have professional testing equipment with a dummy load for the amps, you won't be able to level-match them 100% identically, and if they aren't matched identically, you could send more power to one sub than the other, which will cause one's excursion to be greater than the other, which could cause.... oh hell what do they call it... basically the motion of the more powerful one causes the other to absorb some of that motion, which in turn produces an electromagnetic current in the voice coil of the 2nd sub which can ultimately cause problems.

4. ALWAYS keep your amps well vented. Every time you raise the amp by 10*, you cut its life in half, i.e. an amp playing at 100* will last twice as long as an amp playing at 110*.

 

You may want to check out this site if you are building a custom box.

http://www.linearteam.dk/index.html

It's pretty cool. The guy that posted it said that he has another program that's supposed to be even more accurate, and has more options.......but he hasn't posted it yet.

If you go into the "Program" link on the top tool bar, don't click on it, and another menu will drop down. Use the "ISDonline" section. It has a few options that you can use.

Or if you want, you can download a similar program right to your 'puter. It's (obviously ) under the "Downloads" menu.


Maybe Jim can elaborate more on how usefull this program is?

AJ

 

I've never used the program. I have yet to find a "free" or even affordable box modeling program that's worth a damn. Most good installers pay $500 and up for their box modeling software, which isn't practical for the amount of stuff I build. Most of the time if you take the manufacturer's suggestion and add 15%, you're golden.