The terms gain, volume, and distortion tend to be used interchangeably in music and audio. They get thrown around without regard to what they actually mean.
Aren't gain and volume the same thing?
No. They are not.
This is something that trips a lot of newer producers.
A lot of times you'll hear the term gain when someone means the overall volume or distortion. Despite being used interchageably, the gain, volume and distortion aren't necessarily the same thing.
For starters, you can add gain without distorting the signal. Similarly, adding gain to your signal is not the same as adding volume.
What is gain in music? What is the difference between gain, volume and distortion?
Today I want to talk about what gain is in music and audio, especially as it relates to volume.
We'll also look at how we can use gain properly to get better sounding mixes and tracks.
Let's talk about these.
What is Gain in Music and Audio?
The meaning of gain in audio amplification is quite literal. Gain refers how much the signal has "gained" from being amplified.
If you pass an audio signal through an amplifier and it comes out the other side twice as large, then there is a gain factor of 2. A gain factor of 1 would mean you've go the same signal coming out as what went in — this is called unity gain.
Unity gain, is the term for the level on a fader or processor that just passes signal through it without boosting or cutting the signal strength. It a more popular concept in analog engineering as the saw above.
At the lower end of the scale, increasing gain will result in a louder signal without adding any distortion.
When talking about gain for a guitar amp, we are technically, although not always, talking about preamp gain.
The preamp takes your weak guitar signal and amplifies, EQs and distorts it, before feeding it into the power section, where all the volume gets added.
Gain about signal strength — how strong an audio signal is, whether it's analog or digital, when it's moving through your mixer, mic, console, preamps, DAW etc.
Technically, gain is the input, it is the first part of the signal chain before it hits any plugin or effects.
Measuring Gain
Both gain and volume are measured in decibels (dB).
This is one of the major points of confusion.
Analog audio is measured in dBv or dBu.
dBv tends to be in consumer electronics whereas dBu comes up in professional audio gear.
Consumer audio equipment runs at -10 dBv and Pro audio gear operates at +4 dBu. That is really a measure of the strength of the electrical signal moving through the equipment.
Digital audio is measured in dBFS. FS stands for Full Scale.
Unlike dBv or dBu which can have both negative and positive values, 0 is the highest possible value for dBFS, meaning dBFS is measured in negative values.
In a digital audio signal, anything above 0 is introducing clipping or distortion into the signal.
You'll see analog engineers working with dBu pushing gain past 0 all the time, but you can never do this a digital signal without introducing true digital clipping. This is a big confusion point.
An analog signal is different from a digital signal.
An analog engineer has to worry about something called, a noise floor and something called head room, whereas in digital audio there is no headroom above 0 because that is the top of the scale.
As soon as you go above 0, the computer has to interpolate or crush or distor or clip somehow, to accomodate the audio signal that's being digitized.
There are different types of gain we need to know. But typically, when we are working in a DAW, all we need to worry about is our dBFS.
However, all gain is additive. That means if you have two tracks at -6 dBFS that are playing together, the total gain will be -3 dBFS. That is how gain works.
You need to check whether you additive gain is pushing past 0. That is often indicated (with red?) in most DAWs.
All the gain of the individual tracks will sum in the master.
Generally, it's better to use gain staging.
Whats is Gain Staging?
Gain staging is a technique for leveling and balancing our gain levels appropriately in the mix. It is basically appropriate gain management throughout the mix to make sure our groups and master output isn't clipping or distorting.
As I said before, gain is something we are really concerned about in audio. It shows us the level of the signals we are capturing, creating, processing and mixing.
By watching and adjusting gain for our individual tracks, we ensure that all signals are at their best level for our specific mix.
All the signals from our track are summed together in a group or our master bus output.
To get good master levels, we need to control our channel levels and balance them appropriately.
Gain staging in analog gear takes advantage of being able to push each set of stem into the sweet spot of sound.
As you can probably tell. Gain staging is different for analog and digital gear, and those differences are worth exploring. In fact I do just that in gain staging. Have a look if you haven't already.
For now, just know that the main idea with gain staging is we want to maintain the gain of our signal throughout the process. We don't want to be overdriving into a plugin.
What is Volume in Music and Audio?
If you pass an audio signal through an amplifier and you keep increasing the gain, the signal will eventually reach the volume limit of the amplifier.
Beyond this point, we can keep multiplying the gain factor, but the overall amplitude of the signal, the volume, won't get any bigger.
Colloquially, volume is how much air is being moved by your monitors (speakers, headphones).
Volume is the output of a signal after going through the plugins and with effects.
Measuring Volume
To make it even more confusing, we have dBSPL where SPL stands for Sound Pressure Level.
Volume is measured in dBSPL. dBSPL measures the pressure of sound waves in the enviroment.
With dBSPL, we are measuring the movement of sound waves in the atmosphere. dBSPL is measured upwards from 0, the reverse of dBFS (gain).
Soft conversion is about 70bB. A jet engine taking off 25 meters away would somewhere around 130 dB. 85 dB is the maximum safe level for continued listening, long-term exposure to anything over will cause hearing loss over time.
**In mixing, it is recommended to use 80 bB with occassional levels higher or lower as required to check for clarity, power and details of the mix.
What is Distrortion in Music and Audio?
Again, if you pass an audio signal through an amplifier, increasing the signal past the volume limit of the amplifier is what causes distortion.
Distortion is modification of the wave form which sees the top and bottom squashed as a signal is amplified beyond the clean handling limits of the amplifier. This results in signal degradation.
When designing a preamp, it's possible to design how much gain it will have and what effect that gain will have on the audio signal.
Low-gain vs High-gain Preamp Distortion
A low-gain preamp design will ensure that the maximum possible gain does not exceed the clean limit of the preamp. It will give a lot of amplification with minimal or no distortion.
A high-gain preamp is designed in such a way that the clean limit is very quickly exceeded as gained is increased. The majority of the signal gain results in distortion.
Power amps can similarly be designed to either prevent or allow distortion but the effect of these are only really noticeable at the upper range of the master volume control.
So, if you want to get all that sweet power valve distortion it is easier done with a low wattage amplifier.
The same thing is true for effects pedals. Any type of boost or drive or distortion pedal will involve amplifying the input signal by a gain factor.
Again, as the gain exceeds the limits of clean amplification, distortion will occur.
Pedals typically supplement this distortion by artificially clipping the waveform using diodes. This isn't gain, as the signal doesn't, gain anything in the process, but is a convenient way of emulating what happens when a lot of gain is applied to an audio signal.
In Conclusion
Gain is simply the numerical multiplication of the audio signal — how much more there is after it has been amplified.
Whether that gain leads to distortion or not is simply down to the design of the amp or the pedal.
Distortion will occur of the clean headroom is low enough and the gain signal exceed the volume limit of an amplifier.
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That's it for this article.
