View Full Version : CD EQ mod in RANE AC 22 for JBL 2445/2385

Rudy Kleimann
08-10-2011, 09:39 AM
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, 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.