i want to build a new enlosure for my 18 btl. ive never done any bandpass box before and now id like to try it.

do you have any suggestions or a website were i can find a good instruction how to build a 6th order bandpass (calculator)?

i have a suv and ~10 cft of space.

6th order bandpass enclosures are hard to get right, and there are no accurate calculators so you'll have to crunch the math yourself.

ive used this calculator: Sixth-Order BANDPASS SUBWOOFER ENCLOSURE DESIGN calculator

after i filled in the parameters i got this result:

http://img685.imageshack.us/img685/6509/unbenanntxf.jpg

it says a negative gain? wtf?

can i try the building with these values? how would the btl sound if the bandpass is built false?

ps: how do i calculate the box on my own?

Do you compete? If not, dont bother.

Unless you are the luckiest man to ever build a box, you will spend a ton of money rebuilding box after box to get it right.

no i dont compete.

but i just wonder if that bandpass of the calculator would sound louder than my ported box now (~ 6 cft, 38 hz) although the bandpass would have negative gain.

no i dont compete.

but i just wonder if that bandpass of the calculator would sound louder than my ported box now (~ 6 cft, 38 hz) although the bandpass would have negative gain.

For louder to the ear I'd tune lower as that will "sound" louder, but probably not meter as well. You're tuned kind of high for a BTL for daily...

my current box is tuned way too high...

but if i tuned it to about 30 hz now the net volume would be around 5 cft which is too small i think.

so im really interested in building the 6th order bandpass.