custom enclosures

[dusterbd]

ok, im needing/wanting to build a bandpass box (the ones with the plexiglass front. thats bandpass, right?). itll hold 2 tens. anyway, i need info on how to construct these monstrosities. any websites or rules would be greatly appreciated. im especially interested on basic engineering principles (airspace, porting, etc) and the distance form the front of the sub cone to the plexiglass. also, what about angles? are they needed, or do they have to be flat? i need to know all i can about this type of enclosure, as i have to construct one under the rear shelf (complete with low hanging 6X9's) of a 72 and a 70 duster. thanks for any help.
mike

[lucky13]

There is a book at Radioshack that explains all about box building. I think it was called understanding stereos. good luck!


Brian

[dusterbd]

ok. maybe i came off wrong. i can already build most any type of box to fit any application (space wise), so i dont need the basics on that end. ive just never done this for a paying customer, so i want to get this one right, ya know? ive also only really ever messed around with sealed boxes, so i dont know the rule of thumb about port sizes. the owner of the 72 wants a bandpass put in because he thinks it looks neat, and im using my 70 as a prototype so i know what im doing. thats why i need to know about just this type. the reason im so concerned is because i know that the size of the different chambers greatly influences the way the subs hit, the frequency range, and the power per output ratio. please give me some help, cause this install will get me enough for the rear i need.
mike

[brian24]

Hey Mike, JL audio has some fantastic info. on different enclosure construction, but I'm not sure you can access it from their website. You may also find helpfull info. in the MECP book. MECP is a certification program for professional installers and I know the older books covered box building and bandpass enclosures. They may have changed the book since I read it but you can order it for about 35 bucks if you think it would be helpfull. I unfortunately havn't built a bandpass either but I know the design is basically a ported enclosure with a sealed enclosure in front of it. as far as the angles go i would avoid placing the subs 90 degrees from each other to avoid cancellation but I think any smaller angles would work fine. You should be able to reduce the required air space because the subs will use the air pressure from the sealed chamber for suspension. Unfortuately I don't know how much you could reduce the space. I hope this helps you, good luck! Brian

[dusterbd]

thanks. ill take a look into it. anyone else have anything for me?
mike

[volare360]

for starters a bandpass is the hardest ones to build
you have to be exact in all the dimentions for it to be right

you will need all the info on the subs-and I mean all the technical data for those subs
and then have a proper program to use

basically a bandpass is a box where one side of the sub is sealed and the other is ported
just like a ported box it has a set frequency that has to be matched to it
but since it is a more complicated design-everything must be close to specs or you will overexcusion the subs or it will not perform properly

since you havnt done a ported box you will have your work cut out for you
read the JL site-lots of good info there
and start looking online for programs-I had a real good program for box sizes-cant remember where I got it from

just remember-dont just throw something together
if it isnt tuned corectly-it WILL blow the subs,and it will not sound good

that is about all the advise I can give
I myself am in about the same boat as you-only done sealed
but in my car I am thinking about a ported or bandpass box sometime in the future

[Juggalo]

don't know if you're still looking for info but if so then winisd seems to be a popular box design program...haven't used it much myself since i too only have dealt with sealed boxes . You can download it at:

http://www.linearteam.dk/

or probably a hundred other sites if you do a search.

A couple message boards that could give a lot of info are:

www.sounddomain.com
www.caraudioforum.com
www.elitecaraudio.com
www.termpro.com
www.carsound.com

good luck

~Juggalo