CD EQ mod in RANE AC 22 for JBL 2445/2385 HELP!

[Rudy Kleimann]

I have a rig I have begun running and maintaining for someone and am doing what I can to improve and simplify his setup. His crossovers are, well, OK and Crappy (DBX 223 and DOD something or other). I want to get something cleaner and quieter than the DOD turd, and address a known issue with his direct-connected drivers in a triamp configuration. I have a RANE AC 22 laying around and know it sounds much better than either of his crossovers, plus has two very useful features: a built-in time delay (horn alignment) control, and a fixed CD horn EQ boost modification via a capacitor inside the unit on the PCB. Simple mod, really- just remove the covers, insert the appropriate value capacitor in the proper location(s), solder, and trim the leads.

Anybody here have some experience in selecting the appropriate corner frequency for an active EQ boost circuit for this application?

The RANE AC 22/23 manual has this chart for capacitor selection:

3 dB Down
Frequency/ Capacitor

2.2 kHz .0027 μf
2.5 kHz .0024 μf
2.7 kHz .0022 μf
3.3 kHz .0018 μf
4.0 kHz .0015 μf
5.0 kHz .0012 μf
6.0 kHz .001 μf

The drivers are 2445J with original "Smooth" Ti diaphragms.
The horns are 2385A 60*x40* horns.
Crossover frequency is ~1KHz to 1.2KHz. -haven't run the system enough to decide yet.

Mids are 2x15" 2035H (which I like very well so far) crossed over at ~100-120Hz from 2x2241 or 2x2242.

I KNOW these things will poop out at ~10-12KHz, but it's a PA system. I just want to get it as reasonably flat without external EQ as I can up to the point where the 2445 falls off the chart. I hate the way they sound trying to push them in the top octave anyway.

[subwoof]

go to JBL's site and put tunings in the file type box. ALl of the cabinets ( which will have that horn ) will be there..

http://www.jblpro.com/catalog/general/technicallibrary.aspx

[Rudy Kleimann]

Thanks for replying subwoof.

I've already dug around everywhere I can think of on the JBL site and came up empty. All the tunings I found are for 1.5" drivers and horns, far newer and better performing (?! different anyway) than an old 2445 on a 2385 (60*) horn. And, the Rane is an analog crossover with 24dB/oct L-R slopes and an optional 6dB/octave EQ circuit -not a DSP programmable controller. The wildly variable results of the DR PA auto EQ is well-known. I'm trying to get a good baseline with a smoother response than can be achieved with his 2/3-octave EQ, and one that can't be tampered with or "accidentally" moved.

I could buy a handfull of caps, soldering iron, etc. and bring my DBX DriveRack and mic over to attempt RTA measurements (sic) on the results of each set of caps and see which one of them works the best, but I'd rather not turn this into an all-day (or two) experiment that doesn't pay. His neighbors certainly wouldn't appreciate that either. Besides, how many times can I solder/desolder caps before circuit traces start lifting or tearing off the board?

Doing it at a gig is pretty much out of the question, unless we could set up several hours in advance. It really needs to be done outside if I don't want to deal with the room effects.

Looking at the data sheets for the 2445, its' PWT and 2380 horn F.R. graphs leaves me with wildly different guesses. The 2385A data sheets' F.R. graph just made it more so.

I was hoping to find something more "Plug and Play" from fellows here that had done something like this already.

[subwoof]

look at the manuals for the 5235 crossover. they made CD cards for both the 2380 and 2360 series horns and SOMEWHERE they mentioned the break point...good luck...

I would suggest the 3.3khz and give it a listen. that sounds real familiar.

[Rudy Kleimann]

Thanks- I'll check it out and post it here if I find it.

I'll post what the results are, whatever I try.

Rudy