Hi folks,
I purchased a pair of custom JBL builds from an old gentleman (86) recently who built these back in the 70's. The cab dimensions are:
18"in wide, 14-1/4"in deep & 28-3/4"in high.
The driver compliment, [ea.] is:12"in 124H woofers, 2105 mids & 2405 HF rads. At the time of purchase the 124H's needed to be re-surrounded, and this I accomplished with the very kind assistance of Rick C. in Florida and his high quality JBL surround kits.
[Thanks again Rick! Breakin' them in as I write. They're great. I'll be talking to you again soon. Very soon.]
The cabinets are almost as impressive as the driver compliment. 7/8"in think solid marine grade ply w/ walnut vaneer. Nice and heavy.
There is also a 1/2"in lag bolt goning through the rear straight through the front baffle, half-way up from bottom up but slightly "inside" from center (hmm?). Each "plane" "sandwiched" between a pair of nuts & 1.5"in washers inside & out. I imagine for front baffle and overall support. [The horizontal line on the right speaker is a stain drip, not a crack]
Grills are quite solid also with 3 lateral 7.5" x 1."in. slots in each side due to their 2-3/4"in. thickness.
Cabinet construction is s.o.l.i.d. solid. Not sure about which model the design que was taken from though not like any cab design I've seen as I recall.
As for the crossovers they're HUGE. I'd say that the layout takes up most of the inside of one side of the 28"in. high cab!
They provide two controls similar to that which is found on L100's/4311's etc. But I'm not sure if they are "Brillience & Prescence" or just [0-100 or cut-unity-boost] attenuation for mids and tweets.
(I'm exploring the possiblity of opening one of one cabs for a clear pic and possible upgrade of the crosssovers, as the rear panels seem to be connected using "Allen" head type screws at the very least.)
Crossover component quality is high, and build quality is capable though, from what I can see, was done by someone that had obviously built on this level before. The 3 inductors (at least the size of hocky pucks) are hand built and very well done.
So, I've included some pics and am open to all impressions, info and hints.
If and when I get the rear off of one I"ll include pics of the crossovers and attempt an interpretation of a schematic.(..uh,huh..)
I'm very curious about whether there were home designed or taken from existing crossover design.
Thanks to all for reading through this and letting me benefit from your cumulitive knowledge and experience. This is a great site and I truly appreciate everyones participation. Things are kind of rough here in Michigan but when I get the chance I will be making a $ contribution to the site in appreciation. Peace everyone,
M.Edz