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View Full Version : How connect a electronic crossover to JBL Array 1400?



jalejos
06-08-2013, 09:16 AM
Hello. I am new to the forum and I have some doubts.
I want to connect an 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. Should we do something else? Is there to remove the internal filters? 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?
Thanks.

Mr. Widget
06-08-2013, 10:26 AM
Welcome to the forum!

Not to rain on your parade, but first a few basic questions.

Why do you want to biamp, and what are you hoping to gain?

Secondly if you jump into biamping speakers you may have fun messing about, but with speakers that are as well integrated as the 1400 Array, if you are not an expert I think the probability of stepping backwards sonically is pretty huge.


Widget

jalejos
06-09-2013, 08:34 AM
I performed some tests using a JBL M553 analog electronic crossover, configured as two way, getting an improvement, especially in music. I think using a DriveRack PA + along with his equalizer, I can get better sound in the room.
Currently I have a power Hypex 3x400W for the three front speakers and a Hypex 4x180W power amp for the other speakers. My idea is to use the Hypex 3x400W amplifier for woofers on the front and a new Hypex 3x180W power amp for the speakers mid / high fronts. The Hypex 4x180W for other speakers.
Do not think it's taking a step back if configured well the set.
Thanks for answering.

4313B
06-09-2013, 09:04 AM
You can look at the voltage drive of the passive filter to get an idea of how the crossover slopes are designed. A standard 700 Hz active filter will never get it done. One improvement might come from being able to actively delay the LE14H-3 a few ms.

jalejos
06-12-2013, 04:38 PM
According to the scheme of the filter

59199
there are two cutoff frequencies 750Hz and 8000Hz.
Node 1 LF
Node 2 HF
Node 3 UHF

59200

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.

jbljfan
06-12-2013, 06:41 PM
if this doesn't help, don't bother: http://www.audioheritage.org/vbulletin/showthread.php?23763-Bi-amping-the-JBL-Model-1400-Array

jalejos
11-07-2013, 03:23 PM
After a few months off, I again take the matter.
I decided not to use the DBX Driverack PA + and use a miniDSP 8x8. http://www.minidsp.com/products/minidspkits/8-x-in-8-x-out
Based on the link above (jbljfan) and making the modifications (bypass LF PCB and short HF filter capacitor 11uF) response curve would be:
60532

I have miniDSP outputs configured as follows:
Low pass filter cut to 500Hz 24dB
High Pass Filter cut to 500Hz 24dB
All this for each of left, center and right channels.
All right this cutoff frequency? What kind of filter would be better, Linkwitz Riley, Butterworth or Bessel? What slope, 12, 24, 48dB/oct?
Any idea?

spkrman57
12-06-2013, 07:55 AM
I think 500hz is a bit low. Maybe 750hz might work better, especially for the HF driver.

Just my 2 cents worth.

Regards, Ron