JBLPRX button settings, definitive answer

Lisa Lane-Collins

Lisa Lane-Collins

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Dec 9, 2012
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Adelaide, Australia
On the back of the PRX615M it looks like the button that switches between full range and monitor mode needs to be pressed In for full range.

Now this has come up in conversation with other PRX users on another thread and they assured me full range mode is accessed by leaving the button out.

This has me completely confused because on the back of the same speaker, mic mode (which appears to require the same button settings as full range mode) is accessed by pressing the button in, and on the back of the 618S-XLF sub, the cross over (again, appears to require same button setting as full range mode on the top box) Also needs to be pressed in to be engaged.

Can't find the stupid manual online, or in my house and want to run these speakers at their optimum... heeeeeeelp
 
Re: JBLPRX button settings, definitive answer

Lisa Lane-Collins said:
On the back of the PRX615M it looks like the button that switches between full range and monitor mode needs to be pressed In for full range.

Now this has come up in conversation with other PRX users on another thread and they assured me full range mode is accessed by leaving the button out.

This has me completely confused because on the back of the same speaker, mic mode (which appears to require the same button settings as full range mode) is accessed by pressing the button in, and on the back of the 618S-XLF sub, the cross over (again, appears to require same button setting as full range mode on the top box) Also needs to be pressed in to be engaged.

Can't find the stupid manual online, or in my house and want to run these speakers at their optimum... heeeeeeelp
Click to expand...

20 seconds on the JBL Pro site yielded this: http://www.jblpro.com/ProductAttachments/DOC_1672.pdf
 
Re: JBLPRX button settings, definitive answer

So I see first button pressed in, second button left out and gain set to 12 o clock for optimum foh performance. Sound about right? It's the having to press that first button in for mains that throws me. Not logical!!!!!! (It is putting a slight EQ curve on everything isn't it? But it would appear that is the intended effect......should I maybe leave it out because I have DSP and graphic EQ and just want the speakers to be flat?)

Screen Shot 2014-03-19 at 12.42.04 PM.png
 
Re: JBLPRX button settings, definitive answer

Now I'm looking at this, it looks a Lot like the polarity button needs to be in for the subs too. ARRRRRGH!

Wait, Oh, now I get it, if running subs, leave Main/monitor button out, don't need a boost, because I have sub

So, correct configuration would be on the subs cross over engaged, polarity pressed in? All buttons out on the top box? (Never had so much trouble understanding the back of a power box before).

Screen Shot 2014-03-19 at 12.47.40 PM.png
 
Re: JBLPRX button settings, definitive answer

It does seem strange that you have to choose to use "main" mode, but that's how they've designed it. :)

It may be one of those things that makes it sound more impressive in the music shop but isn't necessarily better in real use. Choose the one that results in you doing less corrective EQ, then just make sure both sides are the same.

Chris
 
Re: JBLPRX button settings, definitive answer

Chris Nixon said:
It does seem strange that you have to choose to use "main" mode, but that's how they've designed it. :)

It may be one of those things that makes it sound more impressive in the music shop but isn't necessarily better in real use. Choose the one that results in you doing less corrective EQ, then just make sure both sides are the same.

Chris
Click to expand...

Not so fast, Chris. The box was primarily intended to be a stage monitor wedge and when used on the floor, has LF coupling that it doesn't get up on a stand. The "Main" selection has some LF boost to compensate and results in a more "flat" response once the speaker is a meter or so off the ground. The anticipated/intended use as a wedge is likely why Main is an option and not the default.
 
Re: JBLPRX button settings, definitive answer

Tim McCulloch said:
Not so fast, Chris. The box was primarily intended to be a stage monitor wedge and when used on the floor, has LF coupling that it doesn't get up on a stand. The "Main" selection has some LF boost to compensate and results in a more "flat" response once the speaker is a meter or so off the ground. The anticipated/intended use as a wedge is likely why Main is an option and not the default.
Click to expand...

I get that, it's the fact that it's also boosting the high end that makes it seem a bit like a "loudness" button. Is that boost left out of the monitor mode for feedback reasons?

Chris
 
Re: JBLPRX button settings, definitive answer

Chris Nixon said:
I get that, it's the fact that it's also boosting the high end that makes it seem a bit like a "loudness" button. Is that boost left out of the monitor mode for feedback reasons?

Chris
Click to expand...

Not sure, I don't have one in the shop to test.

Again, though, knowing a bit about the application, the HF boost is probably a shelving filter beginning around 5kHz or a little higher, to compensate for air absorption.

Now about my reply to Lisa: it depends on several things, mostly about how JBL designed the alignment. If they specifically say to not engage the "Mains" setting when used with a sub, try that first and see how it works out. If you don't like it, try it the other way. Remember that JBL probably did not factor in the use of a DRPA or similar processor when creating the in-speaker processing. If you have the subwoofer drive "hyped", you may have raised the acoustic crossover point high enough to not need the PA to run as low, but in that case my thought would be to lower the subwoofer low pass filter by about 1/3 octave, maybe a bit more, to compensate for the overlap. Another consideration would be if running the PA full range put too much stress on the woofer or amp, but that's another post.

Have fun, good luck.

Tim Mc
 
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Re: JBLPRX button settings, definitive answer

Lisa Lane-Collins said:
But the picture in the manual suggests to leave that button out when running with subs.... (As I am currently understanding it, button 'in' = low end boost)
Click to expand...

Per the manual, when a 612 or 615 is used with a Sub, the "Main" button should be engaged.

JBL Panels are confusing, but with each series the button is different if the box has a monitor wedge:

On the back of the 612 and 615, the options are:
In = Main
Out = Monitor

But on the page that discusses this button, the verbiage uses "Boost" and "Flat". This is how the 625 & 635 are labeled.
There's a graph that shows what these settings look like. Boost is certainly a smiley face graph.


On the 700 series, they use different verbiage as well.

PRX710, 725 and 735
In = Normal
Out = Boost

PRX712 & 715
In = Main
Out = Monitor

When I use my 615's over subs, I use the "Main" setting, which I thought boosts the low's & high's. I'm going to check this out tonight.
There's no graph in any of the manuals that shows what the "Monitor" vs "Mains" does.

On the older PRX500 series, it's reversed:
In = Boost
Out = Flat
 
Re: JBLPRX button settings, definitive answer

It must be the same, the "1" annotation points to the Main / Monitor switch, and the info for "1" is called EQ Boost / Flat. There isn't a separate button anywhere for "Boost" either.

Chris
 
Re: JBLPRX button settings, definitive answer

Boost and Main is obviously the same, monitor is flat because the proximity to the floor in wedge position causes a bass boost.
It is confusing the way they describe it in the documentation, but ......
 
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