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Pi-alignment for JBL 2240 18" driver
Hi Wayne! Been too long since I talked to you last! Could you run a quick cabinet size and tuning for me please??? I'm looking at running a pair of JBL 2240H's up to 800hz for use as 2-way(larger 1.5" or 2" compression driver on Edgarhorn). I expect the bottom end to drop off around 60hz if my Winisd calculations are close. I'm thinking using 3 cubic ft bot tuned to 60hz. What's your thoughts on this, and would a single coil (on the 2240H) work at 800hz like the 2205 does? If it does, what value do you recommend(maybe 1.5 mH)??? T/S of JBL 2240H (8 ohm) Qts - .23 Qms - 2.2 Qes - .25 Vas - 17 cubic ft Fs - 30 hz Le - 1.4 mH Thanks in advance! Regards, Ron
Re: Pi-alignment for JBL 2240 18" driver
PiAlign suggests a 3.9ft3 box tuned to 50Hz, using a 5.5" x 9.8" duct, 8.4" long. It gives a nice flat response curve with f3 of 60Hz. You can surely run this woofer with just a single coil. Nice and simple. Of course, summing is as much determined by what you have above it, so you'll have to take that into account. The easiest setup is first-order, but like everything else, it works well on some things, not so well on others. I'm using the WTPro/ST system to re-evaluate all my crossovers. The Smith and Larson system imports my existing Spice models so it's an easy progression. What I've found so far is the existing crossovers work great but I'm sometimes able to move component values up or down 10% or so and get a smidge better response curve. Nice to have that kind of visibility and resolution.
Thanks Wayne! I have Bill Epstein's old Model 19 clones he built some time ago and they are 3.5 cu ft and (2) 4" dia x 6.5" long. That should be close enough to work without any mods to the cabinet. Regards, Ron
Let us know how it sounds!