Sub box guru's help please.

Stryker · Post by **Stryker** » Tue Jun 23, 2009 4:17 pm

ok I had to shave and widdle my old box down to fit in my car from my van. it used to be 5.0 cu/ft,2.5 per chamber before. now i have no idea what it is. here's the measurements
-top 12 1/4"
-bottom 17"
height 16 3/4"
width 38"
all wood is 3/4 MDF
there is a middle divider of 3/4 MDF
it's ported and has a 4"wide x 8"long port 2 of them per side.
I would like to know how many cubic feet this is so I can figure out it's tuning freq. I've estimated it at 2.1 cu/ft my sub's have an Xmax of 20mm so I've guessed at the box being tuned at 37.5.... let me know your thoughts .

thx

Thunderdome · Post by **Thunderdome** » Tue Jun 23, 2009 4:41 pm

I,d say your math is pretty close as long as the port is 4x4x8 you didn't give the 3rd dimension otherwise I get 2.0

thats without the sub volume though

Stryker · Post by **Stryker** » Tue Jun 23, 2009 5:59 pm

Cool... ya 4x4x8 I have no idea how much the sub displaces. is it a certain number on the spec sheet??? i do have that.

Post by **smgreen20** » Wed Jun 24, 2009 7:04 am

Box internals per chamber are 2.067 cubic feet. That's w/o port displacement.

I don't have enough time at the moment to do the port calc and port freq.

Stryker · Post by **Stryker** » Wed Jun 24, 2009 10:03 am

[quote="smgreen20"]Box internals per chamber are 2.067 cubic feet. That's w/o port displacement.

I don't have enough time at the moment to do the port calc and port freq.
Sweet!!! thx mang.Thats the size the Clarions req. per the spec sheet, although the port length should be 10.39long That would give me
Fb=35Hz and F3=31.4Hz I have no idea what displacement this woofer is it's a 15.

Stryker · Post by **Stryker** » Wed Jun 24, 2009 10:06 am

I found a site to calculate tuning freq. it's 38.75Hz not accounting for sub displacement.