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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => Pro AV Forum => Topic started by: Wes Wece on September 18, 2022, 03:46:30 PM
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I’m having a strange issue and thought I’d try here to see if someone has an idea of what the issue might be. So for starters I’ll list my PA setup. Allen and Heath QU-16 mixer going to a DBX PA2 driverack, the driverack crosses over to a QSC GXD 8 amp to 4 Carvin TRS-1503 speakers. The subs go to a Behringer iNuke 6000 amp to Carvin LS-1802 subs.
The issue: It’s been reported that several times in an hour that ALL speakers cut out for about 1 second. The cut out is preceded by a pop. Sound returns as normal afterwards. Inner ear monitors do not reflect the cutout.
My troubleshooting: Since all speakers cut out, it cannot be a cable since you’d only lose 1 side or 1 speaker. It cannot be both amps having an issue because it would have to be a huge coincidence for both to go at the same time. It isn’t a power issue since it happens at different locations and care is taken to split loads. I do have a power strip the mixer and driverack both plug into but that has been swapped out and tested. The amps are not going into protection mode nor are they clipping. The mixer is not overloaded and is not clipping on any channels. For all speakers to go my conclusion was the driverack so I bought a replacement and it was not the issue. While not impossible, it’s unlikely to be the mixer which is relatively new.
So here is the strange thing, it has been noticed that when my bass player turns on his vocal harmonized pedal, that’s when the cutouts happen. Has anyone ever had a input causing the whole system to cut out? The PA does not cut out when playing music through it from a phone thru a stereo channel. Only cuts out during band performance.
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I’m having a strange issue and thought I’d try here to see if someone has an idea of what the issue might be. So for starters I’ll list my PA setup. Allen and Heath QU-16 mixer going to a DBX PA2 driverack, the driverack crosses over to a QSC GXD 8 amp to 4 Carvin TRS-1503 speakers. The subs go to a Behringer iNuke 6000 amp to Carvin LS-1802 subs.
The issue: It’s been reported that several times in an hour that ALL speakers cut out for about 1 second. The cut out is preceded by a pop. Sound returns as normal afterwards. Inner ear monitors do not reflect the cutout.
My troubleshooting: Since all speakers cut out, it cannot be a cable since you’d only lose 1 side or 1 speaker. It cannot be both amps having an issue because it would have to be a huge coincidence for both to go at the same time. It isn’t a power issue since it happens at different locations and care is taken to split loads. I do have a power strip the mixer and driverack both plug into but that has been swapped out and tested. The amps are not going into protection mode nor are they clipping. The mixer is not overloaded and is not clipping on any channels. For all speakers to go my conclusion was the driverack so I bought a replacement and it was not the issue. While not impossible, it’s unlikely to be the mixer which is relatively new.
So here is the strange thing, it has been noticed that when my bass player turns on his vocal harmonized pedal, that’s when the cutouts happen. Has anyone ever had a input causing the whole system to cut out? The PA does not cut out when playing music through it from a phone thru a stereo channel. Only cuts out during band performance.
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Mac
admin
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check wiring
JR
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check wiring
JR
As I’ve already stated, if it were xlr or speakon cables you’d only lose one side or 1 speaker.
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The issue: It’s been reported that several times in an hour that ALL speakers cut out for about 1 second. The cut out is preceded by a pop. For all speakers to go my conclusion was the driverack so I bought a replacement and it was not the issue.
Is the replacement a driverack too? These are known to produce noise if they lose power and reset. If you don't already have one a UPS has become a standard requirement for digital desks and equipment like the driverack, momentary power glitches that are too fast to otherwise notice can cause reboots and other undesirable effects so it wouldn't be a terrible idea to get one for the rack equipment... even if it turns out that this isn't the problem right now.
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What limiting do you have set up in the DRPA2? By chance are you hitting the input limiting/compression really hard, with a long release time it could sound like the PA cut out.
Are the power amps on the same power strip as the mixer and DRPA2?
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Is the replacement a driverack too? These are known to produce noise if they lose power and reset. If you don't already have one a UPS has become a standard requirement for digital desks and equipment like the driverack, momentary power glitches that are too fast to otherwise notice can cause reboots and other undesirable effects so it wouldn't be a terrible idea to get one for the rack equipment... even if it turns out that this isn't the problem right now.
Yes the replacement was identical. I will consider the UPS. The driverack isn’t powering down though. When I say cut out I just mean the sound. Nothing is powering down or rebooting.
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What limiting do you have set up in the DRPA2? By chance are you hitting the input limiting/compression really hard, with a long release time it could sound like the PA cut out.
Are the power amps on the same power strip as the mixer and DRPA2?
I’ll have to check but think the limiter is off. The power amps are not on the same power strip and in fact I make sure both amps are separated and on different circuits.
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I’m having a strange issue and thought I’d try here to see if someone has an idea of what the issue might be. So for starters I’ll list my PA setup. Allen and Heath QU-16 mixer going to a DBX PA2 driverack, the driverack crosses over to a QSC GXD 8 amp to 4 Carvin TRS-1503 speakers. The subs go to a Behringer iNuke 6000 amp to Carvin LS-1802 subs.
The issue: It’s been reported that several times in an hour that ALL speakers cut out for about 1 second. The cut out is preceded by a pop. Sound returns as normal afterwards. Inner ear monitors do not reflect the cutout.
My troubleshooting: Since all speakers cut out, it cannot be a cable since you’d only lose 1 side or 1 speaker. It cannot be both amps having an issue because it would have to be a huge coincidence for both to go at the same time. It isn’t a power issue since it happens at different locations and care is taken to split loads. I do have a power strip the mixer and driverack both plug into but that has been swapped out and tested. The amps are not going into protection mode nor are they clipping. The mixer is not overloaded and is not clipping on any channels. For all speakers to go my conclusion was the driverack so I bought a replacement and it was not the issue. While not impossible, it’s unlikely to be the mixer which is relatively new.
So here is the strange thing, it has been noticed that when my bass player turns on his vocal harmonized pedal, that’s when the cutouts happen. Has anyone ever had a input causing the whole system to cut out? The PA does not cut out when playing music through it from a phone thru a stereo channel. Only cuts out during band performance.
I am going to throw this out there, but I think my case was a little different. In 2019 I was doing a show outdoors with the QU-16, Powersoft and Crown amps, Ashly DSP. The FOH died for a second and came right back on. I don't remember a "pop". I didn't ask the band, but I didn't see any reactions from them when it happened, so I assumed the wedges didn't die for that second of time. Later when I had time, I turned the QU back on at the shop and had a meter on a channel showing input with nothing connected, so I sent it in for repair.
Here is where my case in a little different, my QU had been sent in once before when lightning took it out and AMS had already told me that other problems may arise after the repairs at that time. I bought a SQ, so the QU has been backup since and I haven't really used it.
I just thought I would mention it since the QU is common in your and my scenarios.
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I am going to throw this out there, but I think my case was a little different. In 2019 I was doing a show outdoors with the QU-16, Powersoft and Crown amps, Ashly DSP. The FOH died for a second and came right back on. I don't remember a "pop". I didn't ask the band, but I didn't see any reactions from them when it happened, so I assumed the wedges didn't die for that second of time. Later when I had time, I turned the QU back on at the shop and had a meter on a channel showing input with nothing connected, so I sent it in for repair.
Here is where my case in a little different, my QU had been sent in once before when lightning took it out and AMS had already told me that other problems may arise after the repairs at that time. I bought a SQ, so the QU has been backup since and I haven't really used it.
I just thought I would mention it since the QU is common in your and my scenarios.
Thanks. I agree the issue could be the QU16, however it’s really only been used about 30 times and therefore is basically still almost brand new. The other thing that makes me think it’s not the mixer is that it only is cutting out when live music is being played. On breaks I play music through my phone thru the ST3 channel and it’s perfect. In my opinion for all speakers to cut out it has to be something that is either originating sound like the mixer or else the xover since the mixer sends all sound thru it. Since I’ve eliminated the xover that leaves the mixer but since we have noticed it’s commonly happening when the bass player kicks on his vocal harmonizer, I have been focusing on that as spiking and causing the mixer to temporarily overload.
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Thanks. I agree the issue could be the QU16, however it’s really only been used about 30 times and therefore is basically still almost brand new. The other thing that makes me think it’s not the mixer is that it only is cutting out when live music is being played. On breaks I play music through my phone thru the ST3 channel and it’s perfect. In my opinion for all speakers to cut out it has to be something that is either originating sound like the mixer or else the xover since the mixer sends all sound thru it. Since I’ve eliminated the xover that leaves the mixer but since we have noticed it’s commonly happening when the bass player kicks on his vocal harmonizer, I have been focusing on that as spiking and causing the mixer to temporarily overload.
Have access to a Radial Ice Cube, Sescom IL-19, or similar audio isolation transformer?
Alternately, is the EFX powered via +48v phantom? Is phantom power switched on for that input if the device does not need it?
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Thanks. I agree the issue could be the QU16, however it’s really only been used about 30 times and therefore is basically still almost brand new. The other thing that makes me think it’s not the mixer is that it only is cutting out when live music is being played. On breaks I play music through my phone thru the ST3 channel and it’s perfect. In my opinion for all speakers to cut out it has to be something that is either originating sound like the mixer or else the xover since the mixer sends all sound thru it. Since I’ve eliminated the xover that leaves the mixer but since we have noticed it’s commonly happening when the bass player kicks on his vocal harmonizer, I have been focusing on that as spiking and causing the mixer to temporarily overload.
While I don't normally like to see someone show up with one of those harmonizer pedals as they usually add noise to the vocal input and are overused, never had one cause the issue your having though.
How are they feeding the reference input to the pedal? Could they be creating an internal feedback loop through the systems? Some of them have a mix function where the reference input can be mixed back into the main output.