Noise at high gain at mains

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This topic contains 12 replies, has 9 voices, and was last updated by Profile photo of abstractnoise abstractnoise 11 years, 1 month ago.

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  • #22120
    Profile photo of hstoit
    hstoit
    Participant

    Hello,

    We have bought the T80 with iDR32 and are doing a lot of exercises with this beautiful machine. We bought it for our church and all different bands and setups in this church. But also a lot of quite moments will be there.
    Yesterday I experienced noise at the mains when pushing it above 0db. And not just a little noise!! Even when all equalizers are switched off. I could not belief my ears. Is this standard behavior?! I was actually shocked. How is this possible on an A&H machine.
    This is getting worser if we use the mic preamps and pushing it up for quite preacher.
    While using the GEQ it is also getting worser.

    What is wrong with it.

    Please advise.

    Best regards
    Hans

    #24604
    Profile photo of Stealth
    Stealth
    Moderator

    Hi Hans,

    Sorry to hear that you are having trouble with your system.

    Could you please give some more detail on your problem e.g.
    what level your gains are set at?
    how many input channels are up in the main mix?
    are some Mic pre-amps significantly louder than others?
    Have you checked cables?

    Best Regards
    Sam A&H

    #24605
    Profile photo of Lieven-Dewispelaere
    Lieven-Dewispelaere
    Participant

    HI,

    Someone had the same problem with noise. It seems that the PAD on the preamps for all the channels was on and the gain way up. Make sure that on the quit channels the preamp PAD is out. I switch the PAD on al the channels off by default.

    regards

    Lieven

    T112/IDR48
    Disclaimer: I disclaim everything. The contents of this message might be totally inaccurate, inappropriate, misguided, or otherwise perverse – except for my name (hopefully I got that right).

    #24608
    Profile photo of PeterM
    PeterM
    Participant

    quote:


    Originally posted by Lieven Dewispelaere

    HI,

    Someone had the same problem with noise. It seems that the PAD on the preamps for all the channels was on and the gain way up. Make sure that on the quit channels the preamp PAD is out. I switch the PAD on al the channels off by default.


    Hi Lieven

    Had the same issue – engineers (?) using 40 plus dB of gain with the pad in!

    Peter

    Peter

    #24609
    Profile photo of hstoit
    hstoit
    Participant

    Thanks for the suggestions.
    I’ll check on all of these issues.
    Tonight we will try this.
    I’ll keep you posted on the results.

    Hans

    #24610
    Profile photo of Mr-B
    Mr-B
    Participant

    Sounds like the PAD story to me, It defaults to on I believe when the channel set up is commenced.
    Which I quite like I must admit.

    Never known an iLive to be noisy[:p]

    #24611
    Profile photo of hstoit
    hstoit
    Participant

    I found the problem.
    I have made a clear and straight away routing. Switched off every group, fx, dca etc. Every IP is directly routed to the mains.
    All processing is switched off, PAD is set off etc. GAIN is set to 25dB for all IP’s.
    Then I discovered that there was only noise at the stereo channels.
    While gaining up the stereo channels to max, the noise becomes very loud. The noise is also not steady, but is (not constantly) sometimes moving a little bit to the left and right.
    This is not the fact at the mono channels. Mono channels stays completely silent.

    On the IDR32 side I have not connected any wire on the Input side.

    Could that be the problem? That there is no synchronization between the 2 inputs because the earth is not connected?
    I can not imagine any other reason.

    That means actually that it should be better to setup every channel as mono channel, and using pan to bring in a stereo image.

    My request to A&H is to check this and what could be done to resolve this.

    Please let me know.

    Best regards
    Hans

    #24615
    Profile photo of Mr-B
    Mr-B
    Participant

    What happens when you load the input? try putting a resistor across the input (something around 10K ohms should be OK) then turn the gain up and see if the noise is still there, I don’t see how it could be ground related unless the noise were in the 50-100Hz region.

    Do you have anything connected to this input?

    #26023
    Profile photo of NCPC
    NCPC
    Participant

    Hi. We are also a church and learning the iLive T112 with IDR48 on the back end.

    We have increasingly become aware of noise creeping into our mix. Since it has been getting increasingly noisy, logically, it is likely due to changes we are making.

    We have established that all of our noise is coming from pre-amp gain settings. Also, the noise seems to sometimes have a way of getting out even if the channel is muted at the board.

    By reducing EVERY PREAMP INPUT gain to 25db or below, we are able to reduce system noise to “acceptable” levels, though I wonder how we even get ANY noise in a completely DIGITAL board with no instruments plugged in?!?

    Some of the volunteer band have inexpensive instruments which require that we boost the preamp to above 35db which brings with it enormous noise that is distracting and unacceptable.

    We are using relatively inexpensive Direct Boxes, (Rapco db100) and I wonder if using ACTIVE Direct Boxes will reduce our problems by allowing us to keep the iLive’s preamp inputs below 25db?

    The bigger picture for me is that I find it completely unacceptable that a board with this one’s cost should have such preamp issues at all! It’s like buying a stereo that clips to distortion before you reach “5” when the volume knob goes to 11.

    Any help is appreciated.

    Please be kind, church volunteer!

    Denis (or some other volunteer)

    #26025
    Profile photo of Biggsounds
    Biggsounds
    Participant

    Um, yes, a $25 DI box running into a $25000 system would seem to defeat the purpose somewhat ;)
    I’ve had some induced noise issues but they’ve been related to pads also (either at the system or inadvertently switched on at the DI).

    iDR32 mixrack
    Asus N61 Laptop (x2 wireless)
    Sennheiser IEM (for PFL)
    Dante card (soon!)

    #25967
    Profile photo of Mr-B
    Mr-B
    Participant

    Still sounds like another case of the pad and the finger to me.
    Ran two racks in Dual mode the other weekend lots of microphones some pad in and some pad out only noise was the local wildlife at the venue mostly Peacocks[8D]

    #25975
    Profile photo of kentlowt
    kentlowt
    Participant

    If you are boosting the gains a lot on the inputs it’s just asking for noise. Get your instruments and imputs to a decent level so your not having to boost like that. Check the pad settings as the above posts have stated.

    112T/IDR48/IDR16

    #26032
    Profile photo of abstractnoise
    abstractnoise
    Participant

    I too found some channels to be noisy on the IDR32/48-based systems I used, and tracked it down mostly to a pad being used on an input channel with gain up past 30dB. Reducing the gain and poking the PAD button to turn it off soon sorted it.

    Also I found that swapping the IDR system in for our previous Soundcraft Live8, I’ve had to increase the system gain at the amp processors by 10dB to get the same sound levels out for the relative levels displayed on the board. This resulted in more headroom across the whole mix, and less background noise in the mix as I was needing a lot less gain at the mic pre’s. I always did prefer to run my analogue desks pretty hot in live mix situations, which is a habit that doesn’t translate well to digital systems.

    “A computer once beat me at chess. It was no match for me at kickboxing.”
    -unknown.

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