Fs 46, 42
Re 5.3, 5.3
Qms 5.1, 4.6
Qes 0.42, 0.39
Qts 0.39, 0.37
Vas 225L, 275L
Mms 53g, 53g
Cms 222uM/N, 271uM/n
Bl 14TM, 14TM
Rme 37, 37
Sd 845 sq cm, 845 sq cm
Le 1.3mH@1kHz, ditto
Rg 0.91 degC/W, ditto
Rt 1.56 degC/W, ditto

Power test 50-500Hz 40V RMS (250W) Free air for 100 hours

Leap motor constants Krm 8.47mH Erm 0.696
Krm 17.7mH Erm 0.667

The graphs show - 10 dB at about 25 Hz rising to 115 or so and peaking near 120 at almost exactly 1.6kHz with a zoom up after to 2000Hz and then rapidly falls off. Unfortunately, after further review, it seems the graphs were plotted in an 8 cu ft sealed enclosure. Oh well.

There are several graphs of the 2418 horn. One is called EPR Plane Wave Tube Response, one is a waterfall looks like a Melissa, and others. There is a data sheet that reads that freq resp is +/- 1 dB 1000 - 6000 Hz,etc. There are also T/S Parameters for the 2418:

Fs 1000 Hz
Re 3.7 ohms
Ret 8 ohms
Sd 15.5 sq sm
xmax .5 mm
BL 5.0 Tesla
Mms 1.1 gram
Le .08 mH
No 25%
Zmin 5.0 ohms Pe 25 watts into zmin

I hope this helps someone. Ain't the people at JBL amazing!