View Full Version : LE 15a Specs
04-21-2003, 12:26 PM
I just wondered if Rob G had the gap length and VC length to hand of these transducers. I know it came up on the old forum but has been lost in the either.
Just finding out how dodgy my recones were. I take it the coil should be midway down the gap? Those dodgy reconers said they sometimes modify these with a overhung coil design, this sounds crazy to me. Totally weak BL would be the result of this surely?
I wondered if there should be a advanced driver spec section on the site with as much detail as possible on the popular models. Giving a bit info than the sales spec. The older specs are a bit vague. Perhaps enclosure volumes used etc. Plus of course a note on that ever popular impedance issue question!
I hope these advanced specs won't be lost in the future. One day JBL drivers might do a 'altec' and stop producing drivers and junk the tooling.:(
PS this should be in 'technical' sorry.
04-21-2003, 01:12 PM
No I don't have gap depth or voice coil winding depth for the LE15A/2215B.
Here are the various impedance specs for the various transducers:
LE15B "8 ohms" with DCR range of 3.1 to 3.9 ohms (C8RLE15B)
2215 "8 ohms" with DCR range of 5.2 to 6.2 ohms (C8R2215)
2215A "8 ohms" with DCR range of 5.2 to 6.2 ohms (C8R2215)
LE15 "16 ohms" with DCR range of 7.6 to 9.2 ohms C16R2215)
LE15A "16 ohms" with DCR range of 7.6 to 9.2 ohms (C16R2215)
2215B "16 ohms" with DCR range of 7.6 to 9.2 ohms (C16R2215)
LE15H "8 ohms" with DCR range of 8.0 to 9.6 ohms (C8RLE15H)
2215H "8 ohms" with DCR range of 8.0 to 9.6 ohms (C8RLE15H)
This is what it is, regardless of what is stamped on the basket. JBL could technically get away with stamping the "16 ohm" LE15A as "8 ohms" because Zmin occurs at roughly 10 ohms. That's why you will notice many of the LE15A networks use 10 ohm conjugates. Like the "12 ohm" 077/2405 that turns up stamped as "8 ohm" or "16 ohm", the LE15A is really a "10 ohm" transducer. Bottom line is, it all depends on where in it's range you're going to employ it and whether or not you use a conjugate or if you are going to pop a 20 ohm resistor across it like is so often done with the 077/2405.
04-21-2003, 01:53 PM
I posted a bunch of stuff about this transducer and it's enclosure requirements before but I failed to save that post.
You can go by the JBL Professional Enclosure Guide.pdf and use a 5.0 cubic foot volume tuned to 30 Hz (two 4" diameter ports having 11" ducts). Or you can go retro and use the old tuning chart! I like the old tuning chart better because one ends up with a tighter, snappier sound at the expense of LF extension.
4.1 to 5.0 cubic feet with a 5.75" diameter port (26 sq in) having a 7.0" duct
5.1 to 6.0 cubic feet with a 5.75" diameter port (26 sq in) having a 5.0" duct
6.1 to 7.0 cubic feet with a 5.75" diameter port (26 sq in) having a 3.0" duct
7.1 to 8.0 cubic feet with a 7.125" diameter port (40 sq in) having a 5.0" duct
I have some old posts related to these elements. Please find them as attachments. They are in text format. Its a bit of a jumble but the info it there. BTW I have a few things on hardcopy as well. Of course they relate only to my stuff, PR15A, LE 15A, 375/2440, 075 and a few crossover threads. I will try to list these later such that if there is any interest I can try to get them scanned or something. I hope it is of some help.
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