PA Level setting basics

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This is something I always think I understand then in the middle of a gig, I'll forget everything and start tweaking things, usually in the wrong order and end up fighting against feedback etc.
So could I ask for someone more knowledgeable than I to give a basic rundown on the best method of setting levels?

As an example, I have the following stages where I can make adjustments:

Acoustic guitar preamp
Channel input gain
Channel Fader
Mixer master volume
Graphic EQ input level
Power amp volume

Metering wise, I have level meters on the output of the mixer, the input and output of the graphic EQ, and on the power amp.
Is there a value I should be aiming for like -6db? I vaguely remember reading that somewhere but probably in the wrong context!

Cheers
Ronnie

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Comments

  • set input gain to your desks recommended settings, usually 0db on PFL fader or -18dbfs if its a digital desk.

    bring faders to unity and then bring master volume up to desired level

    leave power amp or speakers at unity as well - any decent desk these days sounds the same with the master fader anywhere between -15 to +5 or thereabouts.

    gain staging is 75% of feedback elimination, with 25% being finding and eliminating bad frequencies in the room - look up "ringing out a room" on YouTube for tutorials - reference music you know is fine.

    LOW CUT EVERYTHING as far as you can without it sounding thin (except for bass and kick drum) this clears up a mix SO MUCH.

    Make sure everything is compressed correctly, start with a 4:1 medium attack/release ducking about 3-4db when given healthy signal, use makeup gain sparingly.

    if there's still feedback problems try and isolate if its in the monitors or just out front, get surgical if you have to on individual channel EQs


    This should get you in the right ball park - good luck!
    https://www.gbmusic.co.uk/

    PA Hire and Event Management
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  • Thanks for that. :)
    I'm familiar with ringing out the room, I have a Behringer EQ that you can set so individual frequencies light up when peaking which is really handy and I set my HPF to cut everything below 75-100Hz iirc. 

    I use a compressor in my HXFX for the acoustic but don't have one for the overall mix. 

    Where I often come unstuck is if I need to bring the whole level up, should I be adjusting the master on the mixer or the power amp? 
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  • WhistlerWhistler Frets: 323
    Where I often come unstuck is if I need to bring the whole level up, should I be adjusting the master on the mixer or the power amp? 
    The master on the mixer will, ideally, not be raised above 0dB. If more is needed turn up the power amp.
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  • Winny_PoohWinny_Pooh Frets: 7829
    Some live mixers mix at zero. They set all faders at zero and get a balance using just the input gain. That way when you're all playing you only need small fader moves up and down for various soft & loud sections
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  • springheadspringhead Frets: 1611
    If you get your mix roughly right with the input gains adjusted so the faders are sitting at ‘0’, 10dB in hand then the desk is being run at the designed internal running level. I.e. optimum point for noise floor vs headroom.  
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  • If you get your mix roughly right with the input gains adjusted so the faders are sitting at ‘0’, 10dB in hand then the desk is being run at the designed internal running level. I.e. optimum point for noise floor vs headroom.  
    Should I be looking at reaching a particular level on the meters? Obviously I don’t want it maxing out but is there optimum range? 
    I read somewhere about -18db for recording but not sure if that applies on this application or if I’m misunderstanding. 
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  • WhistlerWhistler Frets: 323
    edited February 16
    set input gain to your desks recommended settings, usually 0db on PFL fader or -18dbfs if its a digital desk.
    Listen to @ChrisCox1994 - if it is an analogure desk you can work to 0dB as there will be some headroom but if it is a digital desk then work to -18dB as there is no guaranteed distortion-free heardroom above zero.

    Edit (to make it clear): 0db amd -18dB are meter levels, not the scale measurements on any of the faders.
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  • Whistler said:
    set input gain to your desks recommended settings, usually 0db on PFL fader or -18dbfs if its a digital desk.
    Listen to @ChrisCox1994 - if it is an analogure desk you can work to 0dB as there will be some headroom but if it is a digital desk then work to -18dB as there is no guaranteed distortion-free heardroom above zero.

    Edit (to make it clear): 0db amd -18dB are meter levels, not the scale measurements on any of the faders.
    Thanks, understood now. :)
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  • ICBMICBM Frets: 72741
    edited February 16
    The most important thing to remember is that no matter what the band, and possibly some of the audience, will try to tell you, a good mix is *always* more important than volume. Start by getting each instrument sounding right, the mix balanced and *then* turn it up to where feedback starts, not the other way round. If you try to get everything as loud as possible and then fight the feedback from the vocal mics, all that will happen is that you take away the frequencies which give the vocals clarity and you'll end up with the typical crap gig mix where everything is too loud but the vocals are still muddy and inaudible. It's much easier and very tempting to max the levels of the instruments that don't need it than it is to get the same level from a vocal mic - but wrong. Try to use the EQ to control feedback only subtly - once you get beyond the point where notch filtering is effective, larger changes to the EQ are counterproductive and you'll end up having to turn the gain up to get the level back. EQ is also more effective than volume in creating balance in the instrument mix - don't be afraid to quite radically remove bottom end from things that don't really need it (like guitars) so they don't muddy the mix, and top from things that also don't need it (like guitars...) so they don't create a haze in the vocal clarity range.

    Apologies if this is a bit old-school analogue - I've never used a modern digital desk, but I can't think that the basics will be very different.

    "Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski

    "Only two things are infinite - the universe, and human stupidity. And I'm not sure about the universe." - Albert Einstein

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  • @ICBM thanks, some good habits to get into there. 
    Thankfully I’m only mixing one guitar, one vocal and a looper so not loads of different instruments to balance. 
    Always appreciate the advice on this part of the forum as I’m always learning something new. :)
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