crackling noise?

Forums Forums Qu Forums Qu troubleshooting crackling noise?

This topic contains 11 replies, has 3 voices, and was last updated by Profile photo of volounteer volounteer 1 week, 5 days ago.

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  • #102443
    Profile photo of volounteer
    volounteer
    Participant

    New MD.
    New baseline settings on board. Sound seems better last two weeks …. BUT
    this Sunday there was crackling noise during the pastor speaking.
    I was not sure if I was hearing it from the loudspeakers or if a kid behind me was crinkling a bag of chips.
    Later the MD confirmed the sound was from the audio system.

    Could this be the Qu doing it?
    I would rather think that, with the new settings, the operator du jour did something to cause the problem.
    Anyone with suggestions as to what might have done it ??

    The MD likes things a bit louder than the old MD.
    That mixer operator also likes things louder than the other volunteers do.

    I cannot confirm nor deny that the op may have tried to diddle the compression.
    But I am not sure if wrong attack or other settings would cause a crackling sound.
    I tend to doubt that as this is a new noise to me. So could it be the Qu doing it based on settings?

    #102446
    Profile photo of KeithJ A&H
    KeithJ A&H
    Moderator

    @volounteer –

    There is no processing that would cause crackling noises, though to rule out anything software/setting related please store the show using a USB drive and then send us the whole show folder using https://support.allen-heath.com (and let us know the scene that was in use at the time along with a description of the setup).

    The only thing I can think of that would cause some sort of crackling noise from the Qu would be if either there were a reverb on the mic and the predelay was being adjusted or if the input channel delay were being adjusted. Both of these would be messing with a delay line (like a tap off from a buffer) and so you could create stuttery ‘jumps’ in the signal which might be perceived as crackles. However, these are setup functions rather than something you would adjust whilst mixing (especially in the middle of someone talking!) and I wouldn’t say they sound like a crisp/chip packet either.

    More likely would be a problem with a microphone, cable or speaker/driver.

    Thanks,
    Keith.

    #102454
    Profile photo of volounteer
    volounteer
    Participant

    @KeithJ A&H

    Thanks

    That was helpful.

    I have been unvolounteered from using the mixer so do not know the details of what was changed.
    Somehow now I am an acoustic expert instead.
    Go figure. They want me to help fix the acoustic issues we still have.

    I can envision the new MD adding reverb.

    I can see that operator we had that day making changes on things while live.
    Maybe he will tell us what he was doing. That would be a big clue whether it was settings or other problems.

    They recently added two new RF mikes. But I thought those were only for the orators not the MD.
    This did not sound like any RF interference type I have heard before.

    Possibly it was the speaker/driver as the levels are hotter now.
    Even the MD admitted the SPL levels were too high last week.
    Why does everybody think their ears are calibrated to know the exact level, and won’t measure with an SPL meter?

    So we have some things to look at. Thanks for the pointers.

    Is there nothing they could have done with compression that might have that result?
    I was thinking they had the wrong attack time. But that was just a wild guess.

    #102461
    Profile photo of Mike C
    Mike C
    Participant

    Crackling noise????

    Overload distortion at the wireless body pack, input gain set too high and clipping the
    input.
    A simple bad cable on the lapel or headset mic.

    Where is the mic positioned, is it getting blasted be breath?

    Do all the other inputs sound good?

    What the metering show on the wireless mic receiver, what does the input level show on the mixer?

    Post a clip of the audio or a link to it so we can what the crackling sounds like, listening to it could be very telling.

    #102463
    Profile photo of volounteer
    volounteer
    Participant

    @mikec

    This was pastor RF mike only. Others were okay.

    I now suspect preamp clipping, but bad cables or connectors would be high on the list too.
    The mixer was run by another volunteer last week. He does tend to run things hotter.
    Will have to see if they recorded the sound.
    Maybe it could be gotten from the livestream but they futz things up so much I doubt it would be useful.

    What I heard was like a chip bag being crinkled up behind me. Had thought it was kids behind me doing it.
    But MD said it was from the LR outputs. Now if we had both happening I could have missed the real problem sound.

    #102464
    Profile photo of Mike C
    Mike C
    Participant

    The thin cables on the lapel and headset mics take a beating, give that a closer
    look.

    Also check the input level.

    #102466
    Profile photo of volounteer
    volounteer
    Participant

    @mikec

    I suspect the input level is quite possible.
    The input was just changed from lapel to ear mounted wrap around mike.

    #102468
    Profile photo of Mike C
    Mike C
    Participant

    The input was just changed from lapel to ear mounted wrap around mike.

    And right there we have the mostly likely cause!

    First you need to adjust the gain on the wireless transmitter pac before you do
    anything else, if your clipping the transmitter nothing will fix it further down stream.
    What model wireless system is it?

    After the transmitter is set up then check the input gain on the board.

    #102471
    Profile photo of volounteer
    volounteer
    Participant

    @NikeC

    think it is shure sld but would have to go look to be sure.
    they are relatively new – about 1+ years now.

    but the noise was intermittent last sunday
    I still suspect the volunteer du jour did some changes to the scene
    and then backed them out when the noise happened

    pretty sure the wireless mike is set at the one gain that we always use
    and the rf receivers are never touched just the settings in the mixer if they need it louder when the orator is too low

    #102475
    Profile photo of Mike C
    Mike C
    Participant

    Most likely it’s a Shure SLX, the gain adjustment on those is a three position switch on the side with Mic, 0db and a -10db settings.
    If the headset mic has a hot output and clipping the bodypac try the 0db position.

    With the headset mic where is the mic capsule placed, it should be at the side
    of the mouth, if it is in front of the mouth the breath blast could be an issue.

    What is the headset mic model?

    Link us to the video so we can hear the noise.

    #102478
    Profile photo of volounteer
    volounteer
    Participant

    would have to check on model. but we had used it for over a year with no problem with the lapel mike in it.
    the receivers are all set to keep the signal at the middle level.

    I still suspect the operator did something with gain levels, or there is a bad cable/connector.

    as to video my pc cannot access it to give you a link.
    think they use WIX for their website and it seems to think my xp is too unworthy of seeing its web pages.

    #102480
    Profile photo of volounteer
    volounteer
    Participant

    well the MD and the video guy ( a 15 yo whizkid!) have been doing a lot of work checking everything and rearranging things in the balcony for better? access by FOH operator. At least the mess is getting cleaned up and what we have inventoried.
    they also redid the gain staging in the mixer. instead of one scene to be easy for operators as had been hoped for by previous MD, they will now have one scene for music and one for people talking with totally different gain setups.

    While testing all the equipment cables connectors yada yada they found a number of bad cables.
    replaced same. recent audio problem seem to be gone.

    right now they are doing a number of enhancements to hopefully improve sound.
    They added side speakers with bass earlier today ,
    next they are going to mike the organ loft to feed the livestream sound,
    then on to retuning piano, setting up new 4K camera for livestream, and doing other similar things.

    they found a number of unused RF mikes and receivers which will be useful and they borrowed extra wired mikes from the kids group (they are getting all new gear soon) to be used with stage inputs. Who knew they were just sitting around.

    It may not all be good, but they have made significant improvements in many areas.

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