Mixer set-up basics - newbie

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dbsoccer

Member
I have a Mackie Mix5 mixer and need some help with understanding and settings - starting with the mic gain. I am using a Shure 58 microphone.

Mackie has a set-up video on setting the gain but it is not clear how the gain works with the line level setting for the Channel 1. Per the video, the mic gain is set with the Channel 1 and Main Output Line Levels set at the unity mark. Then the mic gain knob is adjusted so the main output meter bounces around zero with mic input (speaking singing, etc.) equal to that of a performance. But then the person demonstrating zeros mic line level and moves on with some other adjustments.

So with the mic line level at zero and using a performance level input to the mic, the main output meter does not register anything. So what is the purpose of setting the mic gain? Is it like 'tuning' the mic the mixer for lack of a better way to describe it?

At some point the line level of Channel 1 and the other channels will need to be increased and balanced while not clipping the main output, but that's a future question......
 
You set the Gain so that the maximum (loudest) volume doesn't overdrive the input (is there a red 'over' light on each channel?) You balance out each input's volume in comparison to each other with the volume controls on each channel. The main volume is used to control the overall volume.
 
dbsoccer said:
. . .

So with the mic line level at zero and using a performance level input to the mic, the main output meter does not register anything.. . .
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Just starting with the basics - Are all your knobs at the straight up 12-o'clock position as pictured here? Is your mic plugged into the XLR input at the upper left?

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There's a little OL red LED - speak or sing into the mic - on the loudest bits turn the gain up till the lead starts to light, then back off a bit. Done. With the ch 1 rotary level pot at about half, gradually turn up the main mix till the levels on the meters are higher but don't light the red ones - job done. If you have stereo music going into the others, just add that with the other channel knobs.
 
I believe I understand, mjbphotos, that the gain is set so not to over drive the mic's input. But it seems the gain impact on the Main output meter is also affected by the Channel 1 level position. So it seems both the gain and the Channel 1 level control if you overdrive or not. And this may be because there is not a meter strictly for Channel 1.

Spantini, the Maxie tutorial started with a zero'd board meaning, to Maxie, the tape section buttons are out, balance and EQ knobs at 12:00 and the 3 levels all turned to the left as was the Main Mix and the Phones knob. The Channel 1 gain was totally counter-clockwise as well. My mic is plugged into the XLR input.

Once the board was 'zero'd' and to start the process of setting the gain, the Channel 1 Level and the Main Mix were first set to 12:00.
 
Rob, do you mean the LED by the Pan knob? Maxie's tutorial didn't mention this LED. Hmm? I just thought it had something to do with the Pan.
 
dbsoccer said:
.... So what is the purpose of setting the mic gain? Is it like 'tuning' the mic the mixer for lack of a better way to describe it?
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Only slight digression/opinion here, but you asked...

The Gain (sometimes "Trim") control allows you to balance uneven inputs, e.g. on different mic or other source types, so your level/fader controls can all operate in that area around "unity" (or "0"). This is generally where those knobs/sliders have finer control making getting your mix well balanced easier. It also at least suggests another preamp level, which is often necessary for devices with very low output, like some dynamic mics or even guitar pickups (especially if your combo jack does not have an INST/Hi-Z switch and assumes a line level on a 1/4" input).

Many lower end mixers and many (most?) of the powered PA/mixer combination things, even the all-in-one array/speaker on a pole stuff lack a gain control, which I find really annoying...
 
dbsoccer said:
Rob, do you mean the LED by the Pan knob? Maxie's tutorial didn't mention this LED. Hmm? I just thought it had something to do with the Pan.
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Everyone is kinda hitting on things that are close here, but just in an attempt to clarify some things. Fundamentally almost every mixer on the planet has what is in reality an "Input sensitivity" control. As a side note Input sensitivity can also apply to other devices such as power amps. It can be labeled with any number of common nomenclatures. Gain, Input or Trim are often used to describe this function. It is vital to note this is in no way shape or form a volume control. It is essentially an aperture. It widens (raises) or narrows (lowers) input signals entering the mixer itself. It is the foundation of gain structuring (unity gain) and fundamentally without this set properly all else past this entry point fails. It is however an absolute set-and-forget control. The single led light on your pan control is your only guide in setting input sensitivity. Obviously, Input sensitivity can be vastly different between various devices. Mics/keyboards/guitar ect.

The signal flow of almost every mixer of the last 50 years is as follows. The input sensitivity flows into the eq section of the mixer. From there the signal goes to the individual level control. In some cases, the busing structure is next. Common nomenclature is, aux sends or busses. From there the signal(s) flows to the master volume control. The master volume of course is the overall output level from all things going into the mixer.

To properly set input sensitivity, lower both the channel volume and master output volume to zero. They have no bearing on input sensitivity whatsoever. For a microphone, speak, sing, yell at the loudest level you intend to use, and simultaneously raise the gain level until it clips. The red led on the pan control of your mixer will light up indicating clipping. Back off the gain control slightly so the led doesn't blink (or rarely blinks). That, as I mentioned, is a set-and-forget control.

The master volume control should then be set to "U" or unity gain. It can be used to raise or lower entire mixes but generally "U" is the proper starting point. Finally, the individual "level" control is singularly used to raise or lower the volume of the instrument or microphone in that particular channel. Usually, if the input sensitivity is set correctly AND you're using this as a "feed" to a DAW (as opposed to actually mixing something on the board) both the level control and the master output are most efficient (strong signal/low noise) set to "U" unity.

Hope that helps.
 
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This does help. I had understood that the mic gain was a set it and forget. And it makes the most sense if the channel volume and/or master volume are set to zero because, as you said, the gain and the volume are independent. I am curious why the channel 1 gain LED is located next to the Pan knob. Am I to assume OL means overload
 
dbsoccer said:
This does help. I had understood that the mic gain was a set it and forget. And it makes the most sense if the channel volume and/or master volume are set to zero because, as you said, the gain and the volume are independent. I am curious why the channel 1 gain LED is located next to the Pan knob. Am I to assume OL means overload
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I haven't a clue as to why they put it with the pan knob. I'm kinda guessing it's because of available space in such a small footprint. Yep OL = overload. It should be noted that the OL led on your board is in the analog domain, so overs, to a point, are ok. That of course is unlike the digital K20 scale where "overs" create a horrendous clip. As an aside, I'd submit being very familiar with Unity Gain, Analog Metering Scales and Digital Metering Scales is vital in running a hybrid system. Push the analog, leave room for the digital.
 
I guess it’s is closer so you notice it? Warnings need to be visible. Mic gain is set and forget, until the person moves a little bit in or out, or gets excited, or has to read the words and turns their head away. So never really set and forget. It also then prevents your main faders being in the near fully up or down position for normal operation, usually somewhere in the middle so yo7 can easily go up or down. Gain staging, as in setting the right input gain and channel fader position is pretty important.
 
rob aylestone said:
I guess it’s is closer so you notice it? Warnings need to be visible. Mic gain is set and forget, until the person moves a little bit in or out, or gets excited, or has to read the words and turns their head away. So never really set and forget. It also then prevents your main faders being in the near fully up or down position for normal operation, usually somewhere in the middle so yo7 can easily go up or down. Gain staging, as in setting the right input gain and channel fader position is pretty important.
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I suppose there may be times when one might need to adjust the input sensitivity but those times should be kinda rare. The concept of setting input while the vocalist or instrumentalist is at their loudest would always prevent analog overs. I can't remember the spec but headroom after the clip light but before an actual audio clip is fairly high. On the other hand, input sensitivity should never be a component used for increasing volume. That is decidedly not its function. I disagree that futzing with input sensitivity saves one from moving the main faders. The fader's sole purpose in life is controlling volume, and it's really the only place volume should be changed, be it for good old everyday mixing, or addressing someone's poor mic handling. The channel fader is analog so there's no reason a channel fader can't be pushed to its physical limit, provided of course that the physical limit is not crushing something downstream. If one still doesn't have enough gain and headroom on the channel fader (and there's a boatload to be had), I'd find a way to communicate to that person who goofin' up his or her mic technique, well before I'd start restructuring the gain stage. The mantra has always been, all else fails including faders, buses, and master fader, if the input becomes a variable scenario. Input sensitivity, save for extreme situations, should really be fixed.
 
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A lofty aim, but input gain adjustments in the studio and on stage seem very common. I've had hardly any luck ever trying to get singers or even comedians to change their technique, for me. Once it's learned, and they're well known - then they sing like they sing, and you have to deal with it. It's even worse when you have a band that swap mics when they move position. The BV singer does a front number and has a more powerful voice, so the gain has to go down. With good preamps, loads of people tweak the gains to get the faders in a row. Other folk really disagree with this and run the faders at lower or higher positions to maximise the gain structure. I have to say that if I have 4 vocal faders, I'd like them in a row, despite the volume each singer produces - then I can push the person doing the lead and pull back the over load one on some songs.

In the studio, it's even more variable. A noisy song clearly needs less gain than the next song of it's a ballad. I've noticed that every time I swap mics for even speech, a gain tweak is needed to get roughly the same levels on the meters. Adjusting input gain on the interfaces, recorders and mixer is pretty much how it is for me.
 
rob aylestone said:
A lofty aim, but input gain adjustments in the studio and on stage seem very common. I've had hardly any luck ever trying to get singers or even comedians to change their technique, for me. Once it's learned, and they're well known - then they sing like they sing, and you have to deal with it. It's even worse when you have a band that swap mics when they move position. The BV singer does a front number and has a more powerful voice, so the gain has to go down. With good preamps, loads of people tweak the gains to get the faders in a row. Other folk really disagree with this and run the faders at lower or higher positions to maximise the gain structure. I have to say that if I have 4 vocal faders, I'd like them in a row, despite the volume each singer produces - then I can push the person doing the lead and pull back the over load one on some songs.

In the studio, it's even more variable. A noisy song clearly needs less gain than the next song of it's a ballad. I've noticed that every time I swap mics for even speech, a gain tweak is needed to get roughly the same levels on the meters. Adjusting input gain on the interfaces, recorders and mixer is pretty much how it is for me.
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Indeed most of what you submit is true Rob. Particularly when it comes to Live audio, small adjustments anywhere in the signal chain may indeed be appropriate. But this thread was submitted as a "newbie" question and there was some admitted confusion on the part of the OP. Anything an audio engineer chooses to do by way of setting up their own mixing or recording environment is absolutely fine by me, but the fact of the matter remains, input sensitivity, by its fundamental design, is decidedly not a volume control. It is an entry aperture designed to create equal input staging across a variety of sources. Adjusting input gain as a means to increase volume, or put channel faders in a particular spot, changes virtually everything downstream including EQ. Adjusting channel volume post eq and aux sends, via the channel fader, is how most contemporary boards were designed and embryonically makes sense. That's something that I think is fundamentally important to establish when "newbies" ask for help regarding gain staging.
 
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