Questions about the D130 - 075 speaker -New here!

[Davethreshold]

Hi all.

I bought 2 - J.B.L. 2-ways from an estate sale. ($75!! YE-Ha!) They have the D130, and 075 tweeter. Both are 16 Ohm. First, the 075. I just tested the tweeter with LinearX L.M.S. and I am astonished at how efficient it is: 113 D.B. @ 2.83V - 1 meter. The thing is, it starts to drop off at 15K. So I have a number of questions. First, is that drop off normal for this unit, (See pic 1) or did age limit it's top end? I remember back in the day, that I didn't think it went all ultrasonic like J.B.L. said.

2: Is there a rebuild kit for this, that would exceed this performance? I know that the modern tech, is a lot better than back then. I'm thinking with a newer coil/diaphragm, it might go higher. Also, what lens can I buy that would improve the dispersion? Would that be the 077 slot looking lens?

The D130: Kind of the same thing for this unit. The fO measures 49HZ. It should be 40, so I think the surround stiffened up over the years? I tried re-breaking it in at 10-15 Hz for a bout 1 1/2 hours. That didn't make any difference. Can I have it upgraded to a more modern unit with a re-cone?

Any feed back is certainly welcome. Ever since I started DIY speakers a few years ago, I always wanted a pair of these. Years ago, I bought a pair of 001's brand new for $800 retail From Musicraft in Oak Pk. Il. - 175DLH salt Shaker mid, & I think the 0130? or LE115? Darn...I just can't remember the woofer number. The 001's were 2.5 cu' with off white grills, and spun aluminum legs that were about 5" high.

Dave