BomberNYC

well... just as the subject says...anyone here ever build thier own bandpass sub box? I'm feeling cheap and dont feel like paying $75 bucks for a bandpass box from crutchfield. Reason i'm thinking of just building one is because I wanna save some trunk space and it seems like all the pre-built boxes are too big. I was considering getting a basslink but the amount of trunk space a basslink uses up is just a few inches smaller than a component sub with a sub box. I'm planning on putting a 10 inch sub in the bandpass btw. Thanks in advance for any advice!

Asmoran

www.caraudioforum.com

The specs of your box depends entirely on which sub you're getting. Bandpass is extremely easy to screw up. Figure that out first, then do some researching on the above site.

forbidden

Bandpass is the quickest way to destroy a sub. If you do not know what the term band-pass means, you just might want to find out as well. It is good for a great amount of output primarily in the SPL region, but absolutely sucks blue whale for low end extension and output below the tuning frequency (usually up around 70 hz). So don't do it. Yes they look cool but unless they are constructed for the specific sub used, they suck.

MrWigggles

I have to dissagree with Forbidden. The results he describes is when you slap any old woofer into any old prefab bandpass box. Something similar happened to my brother who went to a local audio store in Houston to get his system upgraded - they tried to sell him a prefab ported box that had a Monster wide port that was no more than few inches deep. That would have sounded horrible for my brother's JL 12w0.

My senior engineering project was a 6th order bandpass with a JL 12W6 (original version). It was tested in an anachoic chamber and it had plenty of low extension (somewhere I have a frequency plot to prove it). The only issue is the size which comes in at about 2.5 cubic feet total. (This is no longer a problem since I've use it for the last 8 years in my home theater set-up not my car)

The secret to a good bandpass system is to use the right sub with the right parameters. The fs to qts ratio needs to be a small as possible. For the 12w6, fs = 20.9 Hz and qts = .433 for a resulting ratio of 48.3.

You want your sub to have a value of 50 or less. For instance, the new JL 13W1v2-8 with an fs = 21.9 Hz and qts = .433 comes out to 50.5 which is still workable. However, you are still going to be left with a big subwoofer enclosure similar to my 2.5 cubic foot big boy. (Now you can always go iso-barric with your sub enclosure by adding another woofer to the mix, but that is not very cost effective)

Bomber, if you tell me what 10" sub you would like to use I can design a box for you (remember keep the fs/qts as low as possible in your selection process.)

I am willing to help.

-Mr. Wigggles

truemagellen

MrWiggles and Forbidden are both awesome and invaluable on the forums

but on a tiny car like ours why not sealed?

if you want a 'pretty' bandpass

just make sealed with glassed windows



whatever you do post pics I'm mighty curious...I love seeing different setups

forbidden

Mr. Wigggles and I are on the same page. I think he skipped over the part where I said unless it was a properly constructed box for a specific sub. If one is to modify parameters when building the bandpass box to suit the needs of the sub, then most certainly it can and will do the job. But most people do not go to this length, they want the prefab special of the week and expect a one size fits all kind of response. The end result here is much less than to be desired.

BoosTED

iTrader: (2)

Correct me if I am wrong but I have always been under the impression that bandpass boxes are for SPL not for music quality.

Bandpass don't seem to be used very often and they tend to be big like ported boxes. Some do look nice though.

BomberNYC

Thanks for the input guys.. i think i'm just going to go with a sealed sub box to save space. I was planning on putting a Infinity Perfect 10.1d. thanks Mr. wiggles for offering to design a box for me with all the right parmeters. But like i said.. i think i'll just build a regular sealed box. the bandpass i was considering trying to copy is this :
Q logic Bandpass

But the sub i am planning on building is like Rotary Rasp... but just 1 sub box thoe...

Aten

Mr wiggles
Help I am trying to build a bandpass box for 2 Rockville w10k6dv4 V2