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I have an existing cabinet around 8.5 to 9.5 cu.ft. (depending on port volume, extra bracing, etc.) and would like some port areas and volumes that would tune a JBL 2242 to around 32 to 38 hz. I just want a moderate extension to use this with a small PA system as a subwoofer to help with the lowest octave.
Your suggestions will be appreciated!
Thanks,
Tom
9.0 cu ft @ 32 Hz = two 6" dia ports x 9.4" ducts
9.0 cu ft @ 38 Hz = two 6" dia ports x 4.6" ducts
10.0 cu ft @ 32 Hz = two 6" dia ports x 7.8" ducts
10.0 cu ft @ 38 Hz = two 6" dia ports x 3.4" ducts
Giskard to the rescue as always...thanks!
Since I'm still not quite sure what my final internal volume will be, would you please also post the port lengths for an 8 cu. ft. cabinet? That way I know I'll have all my possible volumes covered and can extrapolate my fine tuning from there.
Thanks again for a quick and concise rsponse.
Tom
Ok.
I see you changed the volume range from 9.0 to 10.0 to 8.5 to 9.5.
The last pair of 9.0 cu ft enclosures I built for the 2242/2245 had 1.2 cu ft of volume displacement due to the driver, ports/ducts, and bracing. Practically all of that displacement was gained back with the addition of 2" OC fiberglass on each side panel and the back panel. In other words, I started with a 9.0 cu ft gross physical volume and ended up with a 9.0 cu ft net effective volume. Cool eh? :p
8.5 cu ft @ 32 Hz = two 6" dia ports x 10.4" ducts
8.5 cu ft @ 38 Hz = two 6" dia ports x 5.3" ducts
9.5 cu ft @ 32 Hz = two 6" dia ports x 8.6" ducts
9.5 cu ft @ 38 Hz = two 6" dia ports x 4.0" ducts
The previous answers were via BB6P
Here's via the old JBL tuning formula
8.5 cu ft @ 32 Hz = two 6" dia ports x 11.375" ducts
8.5 cu ft @ 38 Hz = two 6" dia ports x 6.25" ducts
9.5 cu ft @ 32 Hz = two 6" dia ports x 9.5" ducts
9.5 cu ft @ 38 Hz = two 6" dia ports x 4.875" ducts