Another request for erudition: Drive vs. Gain vs. Volume (Level)

VittorioAngelo

Inspired
Hello All;

My last request for an erudite explanation of Input Level produced such a wonderful response, I'd like to kindly request another round.

Might I ask for an erudite explanation of Drive vs. Gain vs. Volume (Level)? My Google searches have resulted in a terminology soup that my limited capacities of reasoning are unable to decipher.

My basic understanding is this:
  1. Drive: The amount of signal introduced to the block
  2. Gain: The amount of intra-block input to a component of the block
  3. Volume: The volume delivered to your ears
My confusion comes in reading the blocks manual where:
  1. We've a "Drive" block. My caveman-like understanding is that these are simply distortion/boost/fuzz. But, upon closer inspection of the manual, I feel I'm missing some important information.
  2. We've got a parameter labeled "Input Drive".
    In the manual this also referred to as "gain/distortion"
  3. We've also "Overdrive"
  4. We've intra-block drive, as with the chorus blocks
  5. We've a "Gain Enhancer"
  6. We've "High Gain" amplifiers
...and many other references to "drive" and "gain" in various different usages.

Again, thank you very much folks. I'm very glad to be able to learn from this erudite community.

Vittorio
 
The three terms are often largely interchangeable. They all refer to a signal level or changes to it. There are no strict rules about when to use each, so different folks use different terms for the same thing. For every use of one of these terms there are plenty of exceptions where different terms are used. For the most part they all refer to a signal level or a control that affects that level. Whether that is an input level, an output level, a boost level, an electrical signal, or sound pressure levels is usually dependent on the specific device and context.

On a very basic level:
Drive = to push or hit something
Gain = an addition or increase in something
Volume = the size or amount of something

You can extrapolate that to audio.

Drive = how much signal is pushed into a circuit
Overdrive = pushing too much signal into a circuit (for it to stay clean)
Gain = an increase in signal level in a circuit ( you can also have negative gain or a decrease of signal )
Volume = how much signal level you have in a circuit
 
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Agreed^

One other aspect that confuses matters, is despite all controlling signal levels, the way that affects the sound depends on if those levels are becoming loud enough that they overdrive/clip/distort instead of getting louder. When you turn up distortion/saturation/clipping (also referred to as gain confusingly... the high gain (level) signal leads to more distortion, but distortion itself isn't technically "high gain" though it's very common to refer to amps with lots of available distortion as high gain amps)... when you turn up the level into one of those distorting stages it won't get any louder, but it'll distort more instead because it's reached a level of maximum volume.

So these knobs are referred to as Volume, Level, Drive, Overdrive, Gain, Pregain, Post-gain, master, etc interchangeably, arbitrarily, or sometimes situationally depending on the amp makers whims. I include Master Volume because, despite it being primarily a volume control you can definitely turn it up loud enough that it stops getting louder and instead starts distorting the power amp.

So these are all just signal level controls, but depending on where the are in the signal path and how much headroom (available volume before distortion) is available to them they can behave a number of ways, and can even go from controlling volume for part of their range then distortion for the next part of their range.

Take a Drive pedal (named for overdrive pedals perhaps, but also called distortion pedals, dirt pedals,fuzz, etc). Usually they will have a Level and a Drive control. The level control has a lot of headroom, it primarily affects signal level/strength/gain(meaning loudness)/volume by making it louder or quieter (stronger or weaker). The drive knob is usually low headroom: It connects to a diode or transistor or something which is already near the peak of it's headroom, and turning it up just increases the saturation/distortion/clipping/drive/overdrive/gain(meaning distortion).

You can probably blame this on amps that had a Gain knob as a volume (signal level) knob but people learning if you turned the gain way up it would cause distortion. Some of these names (many of which are technically incorrect) caught on for their new meanings.
 
Yep it can be nice and confusing. The Gain control on a Mesa Dual Rectifier does basically the same thing as the Volume control on a Fender Twin Reverb. Both control the signal level after the input tube stage.

That control in the Axe FX for both models is called Input Drive. ;)
 
The three terms are often largely interchangeable. They all refer to a signal level or changes to it. There are no strict rules about when to use each, so different folks use different terms for the same thing. For every use of one of these terms there are plenty of exceptions where different terms are used. For the most part they all refer to a signal level or a control that affects that level. Whether that is an input level, an output level, a boost level, an electrical signal, or sound pressure levels is usually dependent on the specific device and context.

On a very basic level:
Drive = to push or hit something
Gain = an addition or increase in something
Volume = the size or amount of something

You can extrapolate that to audio.

Drive = how much signal is pushed into a circuit
Overdrive = pushing too much signal into a circuit (for it to stay clean)
Gain = an increase in signal level in a circuit ( you can also have negative gain or a decrease of signal )
Volume = how much signal level you have in a circuit

Thank you very much mr_fender. The definitions you provide will go a long way for me.
 
Agreed^

One other aspect that confuses matters, is despite all controlling signal levels, the way that affects the sound depends on if those levels are becoming loud enough that they overdrive/clip/distort instead of getting louder. When you turn up distortion/saturation/clipping (also referred to as gain confusingly... the high gain (level) signal leads to more distortion, but distortion itself isn't technically "high gain" though it's very common to refer to amps with lots of available distortion as high gain amps)... when you turn up the level into one of those distorting stages it won't get any louder, but it'll distort more instead because it's reached a level of maximum volume.

So these knobs are referred to as Volume, Level, Drive, Overdrive, Gain, Pregain, Post-gain, master, etc interchangeably, arbitrarily, or sometimes situationally depending on the amp makers whims. I include Master Volume because, despite it being primarily a volume control you can definitely turn it up loud enough that it stops getting louder and instead starts distorting the power amp.

So these are all just signal level controls, but depending on where the are in the signal path and how much headroom (available volume before distortion) is available to them they can behave a number of ways, and can even go from controlling volume for part of their range then distortion for the next part of their range.

Take a Drive pedal (named for overdrive pedals perhaps, but also called distortion pedals, dirt pedals,fuzz, etc). Usually they will have a Level and a Drive control. The level control has a lot of headroom, it primarily affects signal level/strength/gain(meaning loudness)/volume by making it louder or quieter (stronger or weaker). The drive knob is usually low headroom: It connects to a diode or transistor or something which is already near the peak of it's headroom, and turning it up just increases the saturation/distortion/clipping/drive/overdrive/gain(meaning distortion).

You can probably blame this on amps that had a Gain knob as a volume (signal level) knob but people learning if you turned the gain way up it would cause distortion. Some of these names (many of which are technically incorrect) caught on for their new meanings.

Thank you IronSean. Seeing the variety of terminology, and how they are used is very illuminating.

But, as you mention, also confuses things. lol.
 
Yep it can be nice and confusing. The Gain control on a Mesa Dual Rectifier does basically the same thing as the Volume control on a Fender Twin Reverb. Both control the signal level after the input tube stage.

That control in the Axe FX for both models is called Input Drive. ;)

Nice tip. Thank you again!
 
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