DriveRack PA+ with JBL Syntesis Array

jalejos

Hello. I am new to the forum and I have some doubts.
I have a HC with:
Onkyo PRSC5508
Hypex DIY 3x400W for front speakers LCR
Hypex DIY 4x180W for surround speakers
JBL Synthesis Array 1400 for LR
JBL Synthesis Array 880 for Center
JBL Synthesis Array 1500 subwoofer
JBL Synthesis Array 800 for surround

I want to connect the Onkyo processor to an electronic crossover for bi-amplifying a JBL 1400 Array. I had thought of the electronic crossover DBX DriveRack PA+.
In the Array 1400, I have to remove the connector bridges to connect the two power amplifiers. One power amplifier for the lower frecuencies and other for mid/hight frecuencies. Should we do something else? Is there to remove the internal filters of Array? What's cutoff frequency to put in the DBX? In the manual of the array, 700Hz and 8kHz mark the filter cutoff frequency, or make a autoEQ in the DBX?
Need two DriveRack PA +, one for front left / right configured as bi-amping, other for center. The second channel of this unit? I can use it to control a subwoofer?
Thanks.

Dra

Do not do an Auto-EQ until AFTER you set up the filters. The filters stated in the manual should be used (the one I saw said 750hz & 8Khz). The problem I see is that the cab is already designed to be bi-amped, but with "full range" amps. Each input appears to have hi & lo pass elements in play. By-passing the woofer passive x-over is no big deal, but the mid-hi will be a problem. What to do about the hi-pass for the mid horn except raise the input signal high enough so that the filtered input doesn't overlap the filter of the internal board? This of course forces you to raise the woofer's upper range to a place it may not be suited. Doctoring the mid/hi board to eliminate the 750hz filter altogether would help, but I am not the person to give advise on just how. Try JBL tech support.

So you need 3 independent channels of processing, but would like a 4th for the sub? Like you said that would require 2 DRPA+ units. You will definitely need the Auto-EQ to tune them back up, or use some other testing equipment.
There are some 3 input channel units on the market. DBX has a 4 channel (4800), but ^^^$$$^^^.

I believe that you are undertaking a difficult task. If you succeed, the improvement COULD be worth it. If you fail, it will be an expensive experiment ($1000-$1200).

DRA

jalejos

OK.
According to the scheme of the filter,



there are two cutoff frequencies 750Hz and 8000Hz.
Node 1 LF
Node 2 HF
Node 3 UHF



Since it is biamp and, considering the response curve, I think putting the cutoff frequency at range 500-750Hz, both low-pass to high-pass, should work without problems. You may have to adjust the output level, as you say.
The JBL tech support, no answer.