I'm thinking about making mini (ish) Econowaves using JBL 2123's. Thoughts..

Looking at using as a B speaker to sometimes help surround AND when I want to crank it up, I put less risk on my good speakers. For those that know, do you think this would work ok?

JBL calls it a mid-range driver. Easy to use for an ewave-type 2-way speaker but looks like you will need to run a woofer/subwoofer up to at least 150 Hz to make it work. Great driver for a really big 3-way or 4-way design?

http://www.jblpro.com/pub/obsolete/2123.pdf

Probably best to use it the way JBL did, as a midrange:

http://manuals.harman.com/JBL/HOM/Technical Sheet/4344MkII ts.pdf

That document has a few clues as to where it sounds good:

AURAL SWEEP TEST SPECIFICATIONS:
• System Aural Sweep Test 6.0V Input 30 Hz to 22 kHz
• L.F. Aural Sweep Test 5.0V Input 30 Hz to 500 Hz
• M.F. Aural Sweep Test 4.0V Input 100 Hz to 2 kHz
• H.F. Aural Sweep Test 2.83V Input 1 kHz to 10 kHz

So it is crossed over somewhere between those test points of 100Hz and 2 kHz.

I used the LF & MF circuits from that network with my 2123H's and it works great in between a 2235H and an 4430 top. I did need to tweek the lower end of the HF by decreasing the cap value till it sounded right.

It would work down to 150hz or so in a small box.

You can use the 6x6 horn and cross it at 2k using the eWave crossover.

If you already have them, knock yourself out. You'll need a sub. I had a pair of 2123s and wanted to do the same. I LOVED my JBL 4612s with JBL's 2118. So I looked at a clone that would be the same form factor and performance. You know what I did after modelling all of those drivers? I went with an Eminence Delta 12LFA in a sealed 1.2 cu. ft cabinet with the econowave top end (D220Ti/Pyle) and Pi3 low end crossovers. Beats the PANTS off both my daydreams. Not sayin', just sayin'. The people who have been skeptics and critics and analysts on this board have steered me out of more ditches than I can count. Now I need help with tube audio.

Thank you all for that great information. I think I might have a couple of spare boxes so will try them out. The might sound good as a B speaker with my mains. Thank you again.