Know the Lingo: Live Sound Glossary

Terms used on the cards, in plain English. Beginner terms first, then the advanced ones used in the Going further tips.

Beginner terms

• Gain / trim: How much the console turns up the signal at the very start of the channel. Gain is the mic preamp; trim is an extra digital adjustment after it (Avantis has ±24 dB of trim).
• Headroom: The space between your normal level and the point where things distort. Leave some so loud moments don't clip.
• Clipping: Distortion that happens when a signal is too loud for the preamp or processing. Most consoles show it as a red light; turn the gain down.
• Feedback: The squeal or ring you get when a mic picks up its own sound from the speakers and loops it. Fix it with mic position, lower volume, or a narrow EQ cut at the ringing note.
• HPF / Low Cut / LCUT: A high-pass filter. It cuts the lows below the frequency you set and lets everything above pass.
• EQ: Turning up or down certain frequencies to change the tone.
• Bell / peak: An EQ shape that boosts or cuts a range around one frequency, shaped like a hill or a dip.
• Shelf: An EQ shape that boosts or cuts everything above (high shelf) or below (low shelf) a frequency by the same amount.
• Q (width): How wide an EQ bell is. A low Q (like 0.7) is wide and gentle; a high Q (like 4) is narrow. The Avantis sets width in octaves instead (1.5 wide to 1/9 narrow).
• Gate: Turns a channel down when it gets quiet, so you hear less bleed from other instruments between hits.
• Expander: A softer gate. Instead of shutting the sound off, it turns quiet parts down gradually.
• Threshold: The level where a gate or compressor starts working.
• Range (Depth on Avantis): How far a gate turns the sound down when it closes. 10-20 dB sounds more natural than fully off.
• Attack: How fast a gate opens, or how fast a compressor starts turning down, once the signal crosses the threshold.
• Hold: How long a gate stays open after the sound drops below the threshold, before it starts to close.
• Release: How fast a gate closes, or how fast a compressor lets go, after the signal drops.
• Compressor: Turns down the loud parts so the level is more even.
• Ratio: How hard a compressor works. At 4:1, a sound 4 dB over the threshold comes out only 1 dB over.
• GR (gain reduction): How many dB the compressor is turning the signal down right now. Read it on the GR meter.
• Knee: How gradually a compressor starts working near the threshold. Soft knee eases in; hard knee kicks in right away.
• Makeup gain: Volume you add back after compression, because compressing makes the channel quieter.
• Send: A separate level control that feeds a copy of the channel to somewhere else, like a reverb or a monitor mix.
• Bus: A mix path that collects sends from many channels. A monitor mix and a reverb feed are both buses.
• Aux: A bus used for a separate mix, usually a monitor wedge or in-ear mix.
• Return: The channel where an effect (like reverb) comes back into the console so you can turn it up in the main mix.
• Pre / post fader: Whether a send is taken before (pre) or after (post) the channel fader. Monitors are usually pre so they don't change when you move the fader; reverb sends are usually post so the reverb follows the fader.
• DCA: A fader that controls the level of a group of channels without mixing them together, like a remote control for "all drums".
• Sidechain / key filter: The signal a gate or compressor listens to. A key filter lets it listen to only part of the sound, for example so a kick gate ignores the snare.
• De-esser: A tool that turns down harsh "s" sounds and other sharp, hissy consonants (like "sh", "ch", "z" and "t") only when they happen.
• Playback: Any sound played into the console from a device instead of a live mic or instrument, such as backing tracks, video audio, sound effects, or walk-in music from a laptop, phone or tablet.

Advanced terms (Going further tips)

• Dynamic EQ: An EQ band that only cuts (or boosts) when that frequency gets too loud. On the Avantis it is part of Dyn8, which needs the paid dPack.
• Multiband compression: Splits the sound into frequency bands and compresses each one separately.
• Parallel compression: Blending a heavily squashed copy of a sound with the untouched original. The squashed copy brings up quiet details and adds thickness, while the original keeps the natural punch of each hit. Common on drums and vocals.
• Ducking: Turning one sound down automatically when another plays, for example bass dipping on each kick hit, or music dipping when someone talks.
• Key source: The channel a gate or compressor listens to. "Self" is the channel itself; picking another channel lets you duck one sound under another.
• Insert: A point in the channel where you patch in an extra processor (like a de-esser) so the whole signal goes through it.
• Insert FX vs send FX: Insert FX process the whole channel (de-esser, comp). Send FX get a copy of many channels and are mixed back in (reverb, delay).
• Transient: The sharp start of a sound, like the stick hitting a snare. Transient tools make that start louder or softer.
• Expander ratio: How hard an expander turns quiet sounds down. At 2:1, a sound 1 dB under the threshold comes out 2 dB under. Higher ratios like 3:1 or 4:1 act more like a gate.
• Peak vs RMS: Two ways a compressor measures level. Peak reacts to every spike; RMS follows the average loudness and sounds smoother.
• Subgroup: A bus that collects several channels (like all drums) and goes on to the main mix, so you can process them together.
• Gang / link: Tying the same settings together on two or more channels, such as a stereo keyboard pair.
• Time alignment / channel delay: Delaying one mic slightly so it lines up in time with another that's farther from the source. Fixes a thin or hollow sound when two mics hear the same drum.
• Polarity: Flipping a signal upside down. Use it when two mics on the same source cancel each other out.
• dPack: Allen & Heath's paid Avantis upgrade (Dyn8, DEEP compressor models, more channels). Solo-U and Avantis-U come with it.
• Intermodulation (intermod): Extra "ghost" signals created when two or more wireless transmitters are on at the same time and their signals mix in the radio gear. If a ghost lands on another of your wireless channels, that mic or in-ear pack gets hiss, dropouts or buzz. Coordination software picks frequencies that avoid it.

See also the FAQ and the line check checklist.