What does Gain do on an amplifier

The difference between gain and volume in a live mix

Whether amateur or semi-professional mix on stage or in the studio, two fellow attitudes are often confused with one another. We're talking about the brothers "Gain" and "Volume". The distinction between these two related species is fundamentally important for transparent, powerful and clean sound results. A few thoughts on the difference between gain and volume:

Check it: difference between gain and volume

  • Volume is just the final volume
  • Gain responsible for the clean input signal
  • Importance for practice, leveling
  • Fine adjustment via gain structure
  • Let air up
  • Striking example: guitar amplifier

Volume is just the final volume

Volume is, as the translated name suggests, only the volume without influencing the audio signal. To put it bluntly, many bands would even be helped if only this function was available to them. A live mix that is as powerful as it is dynamic could hardly be created. On the other hand, there would be significantly fewer sources of error.

Gain amplifies the input signal

Gain, on the other hand, amplifies the input signal. However - and this is precisely where the problem of a signal chain lies - this signal is not only present at one point. Instead, the output signal is passed on from all protagonists such as microphone, instrument, effects devices, instrument amplifiers, submixers and integrated preamplifiers to the mixer.

In order to be able to take full advantage of the gain setting, the gain must be sensibly coordinated for each of these protagonists. This means that the gain cluster starts on your instrument or microphone and extends to the last amplification stage, usually on the mixer. Sound engineers speak of gain staging or gain levels here.

Significance in practice

Let us now assume that each one of you has correctly set the gain levels from instrument to power amplifier and is delivering your signal to the mixer. Regardless of whether you have to mix yourself from the stage or are lucky enough to be served by a FoH technician: The process from leveling the signal sources to the overall mix is ‚Äč‚Äčidentical.

Leveling the individual instruments

Initially, all instruments are leveled individually. To do this, press the Solo or PFL button on the mixer. At this moment you can only hear the instrument you are working on. Now you control the gain control on digital mixing consoles until -18 dBFS appears in the display. If you use an analog mixer, you regulate the input signals to a value of 0 dBu.

So you have roughly set up the individual instruments. However, you are still audibly far from a coherent overall mix. The volume of the respective instruments is not yet coordinated in this status. Very simple: You don't want everyone to sound the same, which has been the case so far.

Fine-tune the gain structure

What now follows is the setting of the so-called gain structure. This means adjusting the volume as it should sound in the end result. That means: the singing needs more pounds than the instruments, especially since it should usually be above everything. The flat instruments require less thrust than the solo instruments.

Volume adjustment via the channel faders

The pre-amplification with as little background noise as possible is done via the gain settings. He now uses the channel faders on the console to adjust the volume levels. You are solely responsible for the volume.

Here, too, you have to remember not to tear the channels right up to the top, if possible. In the course of the gig, even with different songs or passages, you are always dependent on room for maneuver up or down.

Changed sound characteristics

The problem: To ensure that instruments or voices sound as natural as possible, the gain is increased as little as possible. However, a number of instruments are simply too weak on the chest on their own to get by without a reasonable separate preamplification in order to assert themselves in the overall context.

Notable problem: background noise and sound distortion

To put it bluntly, you get the feeling that the instrument collapses halfway because it just looks too thin. The input level is therefore raised - carefully (!) - using the gain control. However, the higher it is set, the more background noises are produced and the more audible the changed sound characteristics are. So it is important to find the best possible compromise.

You also have instruments on board that not only deliver an output that can be restrained, but also an immense dynamic range, for example the drums. The drummer doesn't keep pounding wildly on all the kettles and cymbals. Sometimes it plays extremely loud, then again delicately quiet. These dynamic levels must be mapped over the selected gain range.

Let air up and don't get into the red area

It is important to work with little gain and always leave room for improvement. If you always drive the vocals or the quieter instruments just before the red area, the individual signals can supposedly be well controlled. At the latest when it comes to the overall mix, it becomes problematic if you wanted to give an instrument a boost, but there is no more space until the red area.

However, this is by no means the last of the possible difficulties. In addition, the overall mix - this also applies to recordings in the home studio - simply sounds too weak with a gain level that is too low. Admittedly, this doesn't make the brotherly compromise between volume and gain any easier.

Special case of wanted distortion sounds

Instruments such as the electric guitar can be understood as a special case in this context, especially since overdriven sounds are often desired here. The connection is actually relatively simple: on the amplifier (or in the effects device), high gain levels ensure that the signal is consciously and deliberately overdriven. The result is the typically distorted sound.

An all-tube amp has a so-called preamp - the preamp - and an output stage. If the preamp is now approached with a high gain level, the signal is overdriven; the sound becomes dirty, snotty, distorted. If, on the other hand, the sound is to remain clean and clean, the gain must be kept as low as possible. You can find a classic example from Marshall on this product page at thomann.de.

Identical knitting pattern for gain and volume across all devices

The relationship between gain and volume works according to the same pattern in multi-effects devices and modeling amps that work with simulations, as well as floor effects such as distortion, overdrive or compressor.

In practice, high gain levels with a moderate volume setting are used for heavy sounds. Conversely, settings with very low gain and a higher volume potentiometer deliver the desired clean sounds.

So here too: If you just turn up the volume potentiometer, nothing changes in the sound; if you use the gain potentiometer instead, you will change the sound character and volume at the same time. You can understand the volume / volume control as the master-out of the amplifier.

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If you want to find out more about useful stage equipment, please read our article on the subject of "Stage equipment for beginners".

Keywords: live mix, mixer settings, signal chain