Allen&Heath Qu16 Suddenly goes louder and feedback

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This topic contains 40 replies, has 15 voices, and was last updated by Profile photo of Darkmutton Darkmutton 5 years, 7 months ago.

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    Profile photo of Andreas

    At least it is a very high frequency feedback coming from a very near microphone. What about the drum overheads? Are they running through the PA as well? If, that seems to be my first candidate to check.
    Maybe you’re using an always-open talkback mic and accidentially place your headphones near to it.
    I really doubt this is the desk…

    Profile photo of HopeTech

    I think there may be some software issues. We have had the same problem, mostly with Mix channels. Individual channels will suddenly go very loud, causing our band members to pop out their ear buds or off their headsets. This happens not when anyone is making any adjustments and not when someone is screaming into a mic… it just happens. We have also had issues, apparently with the software scenes. Just this past Sunday we were rolling merrily along in pre-service rehearsal when one vocal mic suddenly stopped working. I mean stopped working. We went nuts checking every control adjustment, changing the batteries, nothing got it working again. Last resort, we recalled the scene again and it started working again. Anyone else experiencing these gremlins?

    Profile photo of [XAP]Bob

    Nope – the only real gremlins people have reported en masse have been occasional linked fader moves and consistent dead channels related to phantom power on disconnected DSnake devices.

    Both have been resolved.

    Profile photo of SteffenR


    not much information…

    Profile photo of debzdoodle

    Something that happened to me a couple of months ago – I had the linked fader poltergeist move my faders at a show half a dozen times.
    It didn’t happen again but then a couple of weeks later I had a different weird fader level thing occur.
    I was mixing FOH on my iPad and the guys started making weird faces and gesturing. I managed to work out they were saying they could hear too much reverb. I made adjustments but I got odd looks all night long. I found out from them that the reverb would suddenly become huge and then go back to normal. This happened randomly throughout the night.
    I then had someone point out that there was a bug fix on v1.73 for the linked fader problem so I download the new firmware. Neither of those issues have happened since.

    My point is that maybe it wasn’t just the linked faders that had the gremlins.…???

    Profile photo of Lee7

    I experianced this for te first time last Friday, I was still running FW 1.70 and as I never need to link channels I hadn’t bothered to update to 1.73. Anyway, we had a solo artist who was supporting us at this gig and who wanted to link his desk etc in our system, which I did. Usually I would have put his left & right feeds in to one of the stereo channels, but for some reason I used the line ins on channels 15-16 and linked them.

    The solo artist did about 1hr 15mins without any problems, we went on and about 45mins in to our set the volume suddenly incresed from 0db right up to +10 without any warning, thankfully I had read all the issues surrounding this on other threads so knew what the problem was.

    I have now updated to 1.73 and will run a multitrack session back through the desk and let it run for an hr or so to see if anything similar happens.


    Profile photo of SimonDF

    This is something we have noticed on the Mix1 output.
    The volume will drop significantly at random times with nobody touching the mixer and no feedback etc.
    No GEQ, PEQ, compressor or other processing of the channel. FX returns at zero.

    I noticed it today with the Mix 1 master fader at 0. The level dropped for no reason and when I increased the fader to try and get more level, the volume jumped suddenly (more than due to the fader movement).

    The faders are not crackly, it’s not in a hot environment, nor a dusty one.

    This is on v1.73.

    Has anyone else seen something similar?

    Profile photo of Dags

    Hi there.

    On the QU24 up at a local venue there has been a smiliar problem where something sounds like it is starting to feed back – the frequency rings out for about 3 or 4 seconds (enough to make us go WTF!?) then shuts itself off.

    The house engineer has been trying to isolate why this has been happening but hasn’t been able to find any combination of events that cause this.
    It is just happening randomly, even when running low level acoustic gigs with 2 vocal mics and a couple of DIs.
    Nothing excessive gain-wise & stage monitor levels are running much lower than where we have them for full bands.


    Profile photo of Dick Rees
    Dick Rees

    Do you have proof/evidence that the “feedback” is actually coming through the PA system? Is it always the same frequency?

    Is there any kind of food service in the venue???

    Profile photo of Dags

    LOL. There is another higher pitched alarm that goes off when something in the kitchen beeps. That took a while to get used to 🙂
    Yes, the feedback frequency coming from the PA was the same frequency. The house engineer noticed it first a week or so before I stepped in and when it happened during my shift he told me it has been happening on and off for a little while.
    Can’t say that I noticed it last night though.
    Whether it has been corrected by a firmware update or something else is yet to be seen.

    But thought I’d put in my 0.02c to the discussion in case there is something that needs to be investigated.


    Profile photo of Darkmutton

    i bought my desk about six weeks ago, upgrading from a mix wizard. 3 wks ago i did a wedding for my friend, just his guitar and 1 vocal mic. everything was great, had done 3 songs and all i was doing was killing the reverb inbetween songs by using an asigned soft key on my ipad. Half way through the the 4th song, without touching anything the reverb just took off and the volume got louder and louder. It ended up taking out 3 speaker drivers and i ended up having to get by with just a spare monitor.

    Then just this week, at the beginning of a gig the desk just suddenly started creating white noise as soon as i started to play music on my phone which was plugged into ch15 & 16.

    I’ve spoken to A&H and the desk is now away being looked at but their initial thoughts are a fault on the DSP board.

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