scott foster wrote on Tue, 13 February 2007 00:43 |
I have four spare JBL 2241H's and I'm thinking of building four single-18 boxes for them. I started with Win ISD and Win ISD Pro for a simple reflex design. Can anyone comment on the default Win ISD designs or point me to a better box plan for that driver? Would consider any style. Boxes would be used for 100-150 head pub gigs under 3-way top boxes.
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When I used to use WinISD, it had issues with the accuracy of the Port versus Frequency Tuning.
The Pro version seemed to address the problem.
Don't try to attain a flat frequency response using the 2241 to 40 Hertz then having it roll off gradually. That will require a very large cabinet. You might want to take advantage of the cabinet gain when housing them in less than an optimum sized enclosure. The end result will be a higher sensitivity rating when comparing the 1 watt, 1 meter or 2.83 volt measurements to others.
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In the case that there is not really any better option, playing with WinISD, I see that simple ported boxes between 8 and 13 cu. ft. with tunings from 35hz to 40 hz will work reasonably well. Any tips on what trade offs are best with this speaker? Could I go with a lower frequency extension and accept lower power handling and higher excursion or is it more important to keep excursion low and not try to push the design too low? Should I just stick with the WinISD default for this speaker?
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As far as I remember, 35 Hz is the FS of the driver, and it would be best if you don't go lower than that.
There's going to be a compromise no matter what.
1.JBL 2441 requires a good sized cabinet to offer a lot of SPL
around 40 Hertz without taking EQing into factor.
2.The FS is pretty much standard like the majority of 18 woofers in the market (35 - 30Hz) and relies more on cabinet size to attain those frequencies.
As for excursion, I would it wouldn't be a major factor unless you build a 16 cubic foot cabinet for a single 18, and tune it below 35 Hertz.
The fact is, the smaller chamber will not only restrict the low frequency response, but prevent over excursion at those lower notes.
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Looking at the graphs I see that for the main frequencies, as excursion goes up and power handling goes down that impedance rises. Does that mean that in a "live" setting an appropriate sized and hi passed amp is not going to really be likely to push excessive power into the design anyway?
Any help or opinions welcome.
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Read my above comments. Cabinet size can prevent over excursion or enforce it. Guys who are always concerned with excursion is trying to get every ounce of SPL from the woofer. I can't say I ever agreed on that method for, it comes at a cost. The cost being distortion. It's far better to have four woofers driving
50% of their capacity, than two driving @ 100%
It's a quality issue that many tend to forget is the object of the game.
Best Regards,