When rehearsing yesterday my Allen&Heath Qu16, went automatic very loud and ended with a highpitched feedback
3 mikes where connected
The issue starded when the voice of the leadsinger triggered the sound issue ! -With an aerosmith like Yell-
Then the 2 other mikes had the same issue!
The volume doubled automatic
I must admit that the room we rehearsed in was very hot !
could it be an heating issue ?
Help thanks
What do you mean happened when you that “the volume doubled automatically”?
The singer sang his song
Suddenly the sound went very loud
on al 3 mikes
That’s just plain old system feedback, nothing to do with faulty equipment. You’re just trying to get more volume than the setup will allow and exceeding the amount of available headrooom or the physical setup is wrong.
Im doing this for my living and this never happened
We were Rehearsing for 2 hours on the same volume
Suddenly the mikes went louder and louder till a highpitch feedback
Then I switched it off
Its a volume issue
Could it be coming from overheating ?
Thanks for The tips
Just too many variables. If one mic goes hot into feedback it will sound like all have. The volume will seem to rise rapidly.
What do you mean “went louder”?
Did the faders go up? Did the gain swing round?
Any gates/duckers/compressors?
Any other FX?
If you suspect overheating have you checked the temperature of the QU - what is the environment, is it boxed in, is it outside in death valley?
Did the faders go up? Did the gain swing round?
No all stayed The same
There was a led indicator insert on ??
and a compressor
No external Devices where connected
How do I check temperature ?
Thanks for helping me
Boxed in little hot room
Boxed? Put a fan on it. It only has convection cooling.
I mean in little room sorry
You could of fed the Effects back into it self. When you pull up the Effects 1 or 2 layer up on the right, and and then pull up the top layer you should not have the returns faders up. This happens often. I think its that switch from analog to digital signal flow issue. This will not feed back right away but when it does, its very high pitched and can take off quick.
You probably bump or barely touched something on the mixer. With digital it only takes a very soft touch with any setting, faders, or just any parameter and it will instantly get your attention. I’m sure many engineers have experienced this.
Come on, guys. OP says they’re in a tiny rehearsal space and a single loud yell causes a feedback loop to start between the speakers and the 3 open vox mics. The self-reinforcing loop then takes over getting louder and louder.
No change in any settings, no technical malfunction…just a system trimmed for flat response and operated close to the GBF horizon. Once that is exceeded with the
“Aerosmith like yell” the inevitable ensues: increasing volume from the self-reinforcing feedback loop.
Plain and simple “Live Sound 101”. I’ll take money from anyone who wants to lose the wager.
Its This !
But whats the solution it never happened before ?
Tell him not to yell or set up the vox mic comps as brick-wall limiters so when he screams into the mic it doesn’t drive the system past the threshold of feedback.
Everybody pay up, please…
Run below the gbf limit…
I wasn’t taking that bet.
Where can I check the heat ?
Can you tell me moren about
just a system trimmed for flat response and operated close to the GBF horizon
whats gbf
Gain before feedback.
In a given room, with a given setup there is only so much gain that can be applied before feedback kicks in. So you need to run a bit quieter 
Temperature is shown on the home screen somewhere - can’t recall which tab, but the manual shows it…