Wayne Parham Messages: 18787 Registered: January 2001
Illuminati (33rd Degree)
I agree with you on the quality of the JBL drivers, but I also found what you did, that the upper end response was a little subdued. That's why the L2 coil is jumpered on the JBL 2012H. You'll also notice that the 2012H is an 8Ω driver. So when substituting a 16Ω driver like the 2123J, I'd be inclined to remove the attenuation resistors entirely.
This should get you where you want to be. It's wide open, basically a full-ranger, but then again the horn itself creates an acoustic filter. That prevents it from reaching above 2kHz or so.
Also note that the polarity is reversed in some cases. So be sure to check that too. And if memory serves, the 2123 doesn't reach quite as high as the 2012 in the midhorn, so you may want to shift the tweeter crossover down a smidge.