DBX Driverack PA with JBL JRX125s and 118S

JDTechie

I'm considering getting a DBX Driverack PA, to replace my behringer CX3400 crossover. I have two JBL JRX 125s which require full range signal to be sent to them, and two JBL JRX 118s subs. Does the Driverack PA have the ability to send a full range signal to the 125s, but just lows to the 118s subs?

any help/advice would be much appreciated

Dra

Yes.
You could also send a full range signal to the subs.

But in either case, why would you? Both cases will hurt the sonic purity of the sound.

DRA

JDTechie

JBL JRX 125s need a full range signal sent to them as they have an over complicated built in crossover, so the lower 15\" handles lows, the top 15\" handles mids and lows. if i just sent highs into a 125 cab, the lower 15\" wouldn't be doing anything, which is a waste.

I have 118s to give a bit more volume to the low frequency, so am just wondering whether the PA is the right thing to get.

so the 125s need a full range signal and the 118s need just lows

Gadget

You sir a absolutely incorrect...If you run the JRX tops full range you will have horrible LF response...The frequency plot clearly shows that the response falls like a rock below 100 hz. I imagine with a crossover frequency of 2000hz that the Quasi~ crossover (which helps eliminate the very same LF scrambling (comb filtering and cancellations that occur when two drivers are in close proximity) that were trying to help you avoid by the way...) would fall in the 200-300 hz range...certainly no lower than 150 hz meaning the bottom end woofer handles all frequencies below that HPF.

So as Dra said, DO NOT run those fullrange... depending on amp power I'd recommend no lower than 100 hz... maybe as high as 120 hz.

You will not BELIEVE the difference in the sound you will get IF you follow directions...and put that BEH crap up for sale and replace it with a driverack...I had one once and it was THE WORST xover I have ever used...even the POS DOD crossover was far superior to it and IT was crap!

Does that answer your question?
Gadget
Moderator

Dra

I imagine the lower 15 is filtered at 300hz like the Peavey Sp4's. This reduces mid cancellations within the cab.

DRA

Kyle Abel

We are also running 125's over 118's with a DPA. I found a cross at 106hz or 112hz (I don't have the exact frequency in front of me, but it was the one between 106hz and 120hz) sounds best with this system. I also have to turn down the 125's amps a few dB's to get a good balance between the tops and subs (after proper gain structure of course).