How close is close?

[Regis]

Boy, I've been learning a lot about speakers lately (maybe that's a bad thing!), but I found this Italian website that lists the values for many JBL speakers www.caninialtoparlanti.it/JBL1.htm . Zach is right, those 128H's are a very tough find. Never been sold on Ebay either (not by that name anyway). I compared the various drivers and came up with a few that are pretty close and have been available on Ebay. Maybe the X-overs would have to be mod'd out to accommodate the differences.

I found the following to be very close in spec to the 128H. I'll list the 128 value first, followed by the alternative. Models 128H/2214H, FS 20/23, Vas 9.9/7.9, QMS 7/10.2, QES 0.25/0.25 (same Electrical Damping, different mechanical damping). QTS 0.24/0.24 Pmax (watts) 100/200 Resistance 5.7/5.6, Diameter 10.2/10.2, Xmax 0.31/0.26, LE 0.7/1.3 Sensitivity 92.9/94.05, Efficiency 0.86/1.1 (greater sensitivity = greater efficiency?)

Model 128H/LE14A FS 20/28, Vas 9.9/5.2, QMS 7/6.5, QES 0.25/0.34 QTS 0.24/0.32, Pmax (watts) 100/100 Resistance 5.7/6.3, Diameter 10.2/11.4, Xmax 0.31/0.2, LE 0.7/1.4 Sensitivity 92.9/92.9, Efficiency 0.86/0.95

My question is, just how close is close and will these speakers work in the 41 inch high L-150 cabs and sound "reasonably" good?

[roddyama]

Hi Regis,

The T/S parameters for many of the JBL drivers are available from the JBLPro site.

Both the drivers you've found should have similar low end behavior, but the higher L will cause them to roll off in the mid range faster. Don't know for sure, but they may not react the same to the x-overs in the range from 5-600Hz and up. The LE 14 has the added disadvantage of being a different size (14").