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Author Topic: Dedicated passive wedges  (Read 751 times)

Steven Gregory

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Dedicated passive wedges
« on: June 01, 2024, 09:56:36 AM »

Hi all.
I’ve been successfully using Behringer xair18 with JBL powered mains and wedges for several years.
I recently joined a band using a large passive setup. QSC power and Martin mains and wedges.
I’m trying to configure the system to support dedicated stage wedges (for each player).
Easily done with the powered JBL system. 

on the new system The mains(LR) are operating normally.

The monitor system is the problem.  We’re using 2 QSC 2450a amps To feed 4 monitors.
I’ve set the amps in stereo mode in order to run discreet aux sends to wedges.
The patching seems fine. Signals are getting to where it needs to go. (Aux1 to mon1, and so on..)
But the amps seem to be sending different EQ for channel 1 and channel 2 .
So… mon1 is “bright”  mon2 is “muddy”.  All mixer settings are flat. Nominal.

I’m inexperienced with this type of system. What am I missing?
Thank you.
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Landon Lewsaw

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Re: Dedicated passive wedges
« Reply #1 on: June 01, 2024, 10:33:54 AM »

Are you sure it's not an issue with one of the wedges?  If everything is the same on the output processing from the mixer going to your amp channels, it can only be the wedges themselves.  There's no DSP on those amps.
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Steven Gregory

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Re: Dedicated passive wedges
« Reply #2 on: June 01, 2024, 11:30:22 AM »

Hi Landon - thanks.
Well I've done all the logical cable swapping.   IE: I can move the EQ problem from mon1 to mon2.
I don't see any DSP on the amps (but these units are new to me - could be missing something)
Is it possibly a defective amp? - Is stereo mode the correct mode for this setup?

I see some just daisy chain the monitors, But I can't see how you could run discreet aux mixes that way.
Thanks

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ThomasA(lbenberger)

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Re: Dedicated passive wedges
« Reply #3 on: June 01, 2024, 12:39:03 PM »

Hi Landon - thanks.
Well I've done all the logical cable swapping.   IE: I can move the EQ problem from mon1 to mon2.
I don't see any DSP on the amps (but these units are new to me - could be missing something)
Is it possibly a defective amp? - Is stereo mode the correct mode for this setup?

I see some just daisy chain the monitors, But I can't see how you could run discreet aux mixes that way.
Thanks

Help us troubleshoot your problem.

First:
- get your system running, check for a monitor that sounds 'right' and for the monitor loudspeaker that sounds 'muddy'. disconnect the speaker cable at the muddy monitor and connect it to one of the 'right' sounding ones. (obviously: disconnect this one first). how does it sound now? still right -> problem with the other speaker. muddy -> problem in the signal chain

- if the problem lies within the signal chain:
-- swap the loudspeaker cables (very unlikely cause, but we need to start at one end of the chain)

-- turn off all amps. take out the xlr input from the amp channel that sounds 'muddy', insert it into an unused channel on your board (attention: no level sent to any monitor from this channel, better mute it to make sure!!) and hit PFL. what does the RTA show you? do the same with the 'right' sounding channel's input cable. what's the difference?
-- if the signal from both monitor sends looks the same: swap the XLR-cables
-- if the monitors still sound different: make pictures of both the front and the whole back plates of your amp and post it here. Or swap amps and see what happens.

« Last Edit: June 01, 2024, 12:41:09 PM by ThomasA(lbenberger) »
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Magnus Högkvist

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Re: Dedicated passive wedges
« Reply #4 on: June 01, 2024, 01:04:20 PM »


But the amps seem to be sending different EQ for channel 1 and channel 2 .
So… mon1 is “bright”  mon2 is “muddy”.  All mixer settings are flat. Nominal.

Sounds like the Monitors are Bi-Amped. +-1 from amp goes to Lows in Mon 1 and +- 2 goes to Highs in Mon 2.
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Brian Jojade

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Re: Dedicated passive wedges
« Reply #5 on: June 01, 2024, 02:44:31 PM »

Which amp is this exactly? The picture you posted isn't the RMX2450a.
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Brian Jojade

Dave Garoutte

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Re: Dedicated passive wedges
« Reply #6 on: June 01, 2024, 06:42:05 PM »

Sounds like the Monitors are Bi-Amped. +-1 from amp goes to Lows in Mon 1 and +- 2 goes to Highs in Mon 2.

+1
 Looking at the back photo suggests this is the problem.
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Scott Holtzman

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Re: Dedicated passive wedges
« Reply #7 on: June 01, 2024, 08:13:06 PM »

+1
 Looking at the back photo suggests this is the problem.


The XLR's don't match that would make me insane.  It's a short trip



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Scott AKA "Skyking" Holtzman

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Mike Caldwell

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Re: Dedicated passive wedges
« Reply #8 on: June 03, 2024, 08:42:42 PM »

Ok some if's here....
If your monitors are set up for bi-amp and if you are sending full range signal to both inputs on the amp and if you are using four wire speaker cable wired to pin set 1 and 2 the monitor plugged into channel 1 on the amp will be sending the full range audio to the horn driver in the monitor. Doing that will soon damage the diaphragm.

Was this system in use and working before you joined the band.

That amp in your picture is a QSC PL2 A series that has a built in analog crossover that is set through a side panel in the amp using SIP resistor modules.
That said your amp is shows it is in standard two channel mode.

Brian Jojade

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Re: Dedicated passive wedges
« Reply #9 on: June 04, 2024, 01:49:23 AM »

If the problem is the speakers are set to biamp, plugging a speaker into output 1 would then get different sounding signal if you turn up mix one and then mix 2.

The OP said that the signal is going to the right speakers (only the right speakers??) but sounds different coming out of each mix.

This also assumes that 4 conductor wire is being used.  In the photo, the top cable may be that, but the bottom wire seems a little thin for a 4 conductor. Of course, not enough info in the picture to say for sure.
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Brian Jojade

ProSoundWeb Community

Re: Dedicated passive wedges
« Reply #9 on: June 04, 2024, 01:49:23 AM »


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