I have several JBL 2226 drivers that I am very happy with the sound of but they are loaded into absurdly large quad 15 cabinets. I'm looking at building several new subs to truck pack dimensions ( 22.5 x 30 is our standard footprint ) and am casting about for best ways to design boxes starting with a fixed pair of dimensions and a known driver and come up with suitable volumes and vent sizes. Any suggestions?
Riley,
The 2226 is a great sounding driver (and sought after for home stereo use), but has only 7.62 Xmax- considerably less expensive drivers are available with double the Xmax now.
With an FS of 40, it won't perform optimally tuned much below that.
Designing for sub use there is simply no replacement for displacement, doubling displacement allows for 6 dB more output.
Design always ends up conforming with Hoffman's Iron law- Loud, Low or Small, pick two.
The Iron Law puts fixes certain relationships- to keep port vent air velocity low (like around 15 meters per second) to utilize greater Xmax speakers requires large ports, large ports tuned low become very large compared to cabinet volume, small cabinet volume "wants" higher tunings..
When you design using a program like Hornresp (free) that shows port velocity and Xmax, you can realize the best compromises for the chosen speaker parameters, cabinet volume and Fb.
With "25 Hz the new 50 Hz", I find a tuning (Fb) of around 36 Hz to be the best compromise between size and extension for most pop music- the low note on a 5 string bass is 31 Hz, last century four string basses with 40 Hz as the low note were common.
Art