Until then I scoffed at JBL's, or for that matter any 15" driver as a guitar speaker (too slow, no sparkle, no chime, too dark, etc.), but that old 'verb was an epiphany...
I love 15" speakers for guitar.
I guess on the low end, there would be CTS 15". They don't have as much high end as other 15"s, and their efficiency is on the low side. I was trying out a head a couple of weeks ago through 2-12" and then plugged it into a 2-15" CTS cab without changing the settings, and the volume drop really amazed me.
EVM 15"s are pretty good. I have a couple of Force 15s in a cab and they have quite good high end.
The really amazing 15" speaker for high end sparkle and clarity is the Blue Marvel Peavey uses in the 1-15" version of the Delta blues. I can't find any specs for it, but it must have a high end around 6.5-7Kz at least. It can get brighter than a lot of 12" speakers.
Another alternative to a D130 would be it's close relative - the Altec Lansing 418-B. Like the D130, it has a cast frame, massive magnet structure, aluminum dome cap. The primary difference is a 3" voice coil compared to the 4" of the JBL.
Ok, back to JBL - a little history tidbit for those that might not know.
The "D" series were designed by Harvey Gerst while he worked at JBL. He left JBL to become one of the founding members of Acoustic Control Corporation, where he designed the 260 amplifier.
Of course Harvey wanted to use the JBL speakers he designed for the two cabs that the 260 could be ordered with - the easily recognized 2x15" with horn, and the 4-12".
JBL refused to sell speakers to Acoustic Control Corporation - having something to do with the fact that Harvey worked there. Not quite sure of the specifics of JBL's refusal to do business.
So that's why Acoustic Control Corporation wound up using Altec-Lansing speakers instead.
Harvey is still active in the music scene - this link will get you too a mini-bio:
http://www.itrstudio.com/staff.html