SW-12a twin passives box question

hayden · « **on:** 14 Mar 2006, 06:55 am »

Danny (or anyone else),
I've been attempting to model the sub and twin PR's in a 3.14 cu. ft. box I have that is screaming for use (older project leftover). I can't seem to find the right amount of weight to add to the PR's for a good FR. Any help is appreciated.
JP

Danny Richie · « **Reply #1 on:** 14 Mar 2006, 02:08 pm »

Actually, for that box size I would use a single PR and add some additional bracing to the box to stiffen it and take up a little bit of the air space. Then the stock weighted PR would be just about right.

Making the box larger actually means you can take mass off of the PR to get the same tuning.

hayden · « **Reply #2 on:** 15 Mar 2006, 12:05 am »

Danny,
Thanks for the answer. I forgot to add in my first post that I also wanted to lower the tuning to about 18hz. Would this be feasible with the dual PR's? Thanks in advance,
Jim

Danny Richie · « **Reply #3 on:** 15 Mar 2006, 04:38 am »

The added air space alone with allow it to hit a -3db of 19Hz.

My software will not allow me to model a pair of PR's. I'd have to build one and measure it.