Gain
This is the name given to the amplification of a signal level. It can be expressed as a ratio of the output signal amplitude to the input signal amplitude.

For example:

Gain = Vout / Vin

Gain is normally expressed in dB.

For Voltage Gain use:

Gain (dB) = 20 log10 Vout/Vin

For Current Gain use:

Gain (dB) = 20 log10 Iout/Iin

For Power Gain use:

Gain (dB) = 10 log10 Vout/Vin

Gain Control
This is a device which adjusts the gain of an amplifier. This is normally done by altering the amount of negative feedback in the amplifying system. A Gain Control is not the same as an ‘attenuator’ or a ‘volume’ control.

Gatefold
A fold-out vinyl album sleeve, also used for some Digipack CD cases. Typically Gatefold sleeves either open like a book or they fold out as three sections. Gatefold sleeves are normally used for double LPs, though they may also be used for singles, 12″ singles, EPs, or specials and collectables with certain artwork needs.

Gatekeeper
Music Industry name was given to aggregators and other services who may filter the material available to the public. Gatekeepers include Major labels, national media, streaming service providers.
Name given to websites and services that filter music submissions to record labels, music publishers, music directors etc.

Glass Master
A glass master is used during the CD replication process. It is created by the replicator, based on the submitted mastered recording, as a master for the purpose of pressing CDs. It is a one-off cost added to the price of the first order of a CD run with a replicator. Subsequent runs use the glass master created as a result of the first run order.

Gold Album/Gold Single
In the USA, the RIAA certifies an album or single as gold when it sells 500,000 units. In the world of downloads and streaming, the digital transmission of 10 individual tracks by an artist counts as one album.

Many world territories have different sales thresholds for “gold.”. See https://en.m.wikipedia.org/wiki/List_of_music_recording_certifications for a full list of music recording certifications.

Google Content ID
A method of identifying infringing uploaded content on YouTube using a licensing library. Audio fingerprinting technology is used to identify infringers, however people uploading routinely receive warning emails from YouTube despite uploading legitimate cover versions or even originals with similar titles to known works.

Granular Synthesis
This technique uses small segments of either sampled or synthesised sound to generate a new sound or sound texture.

Ground Loop
This is a condition that occurs when two or more paths to ground exist and an unequal voltage is induced in each of the paths causing a buzz, hum or other noise.

Group
This is a Mixing Desk channel to which a group of audio signals can be routed to allow the treatment and control of the resulting combined signal.

Guitar Neck
A long section of the guitar, normally made of wood, that the strings are stretched over.

Guitar Nut
The guitar nut is a strip, between the fretboard and headstock, on which the guitar strings sit. The nut normally has small notches which are used as guitar string guides.