The Dynamics Family

Step 11

Now draw the family, then say it

Draw each member of the family on the axes. The threshold is −30 dB.

Pick one. Drag dot 1 up or down to bend the line above the threshold, and dot 2 along the bottom to bend it below. Each one you draw right stays on the graph.

Say it in words

A compressor and a limiter both work above the threshold. The difference is …

A gate and an expander both work below the threshold. The difference is …

Expansion is the opposite of compression, because …

Each one asks two things: which side of the threshold it turns down, and how far (by a ratio, or all the way).
Compressor: above the threshold, turned down by a ratio. At 4:1, 8 dB over the threshold comes out 2 dB over.
A compressor makes the dynamic range smaller: the loud and quiet parts closer together.
Limiter: above the threshold, all the way (∞:1). Nothing gets over the threshold, so the peaks cannot clip.
Gate: below the threshold, turned down all the way (or by its range). The noise between the notes goes.
Expander: below the threshold, turned down by a ratio (1:2). The quiet gets quieter, gently: a gentle gate.
Expansion makes the dynamic range bigger: the opposite of compression.
An expander at 1:∞ is a gate; a compressor at ∞:1 is a limiter.
On the graph: input level (dB) along the bottom, output level (dB) up the side, the 1:1 line where nothing changes, the bend at the threshold.

On the paper and in a DAW: the same family

The names you may meet

On the paper	On a DAW's devices
Threshold, ratio	Threshold, Ratio
Compression, a compressor	Compressor
Limiting, a limiter	Limiter (the level nothing gets over is often called Ceiling)
A gate (range)	Gate (its range is often called Floor)
Expansion, an expander	Expander, or the Below side of a dynamics device

On a DAW's dynamics device, such as Live's Multiband Dynamics, Above and Below are the two sides of the line, each with its own threshold and ratio.

Next lesson: Which tool? You hear a problem in a mix and choose the tool that fixes it.

The dynamics panel is our own drawing, in the exam's names. Its graph, its meters and the sound all come from the same numbers: a model of the four processors, made for teaching. The vocal is a recording; the hiss, the hum and the knocks are made in the browser. Ableton and Live are trademarks of Ableton AG. Music Tech Studio is independent and has not been authorised, sponsored or otherwise approved by Ableton AG. Made for a laptop or the whiteboard.

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