# `Mx.Instrument.Vocabulary`
[🔗](https://github.com/mx-music/mx/blob/main/lib/mx/instrument/expr.ex#L70)

The nodes and functions a `defsynth` builds its sound from, named by what they do, with each argument named by its unit.

Numbers: `hz/1`, `db/1`, `log2/1`, `exp/1`, `sin/1`, `cos/1`, `clamp/3` and `select/3`, worked out at once on numbers and when the note starts on its options.
Sources: `impulse/0`, `follow/1`, `time/0`, `sine/1`, `vibrato/1`, `partials/2`, `bowed_string/1`, `air_jet/1`, `saw/1`, `square/1`, `triangle/1`, `pulse/1` and `noise/1`.
Filters: `lowpass/2`, `highpass/2` and `bandpass/2`, at `hz:` with `q:` and `poles:`, `lowshelf/2`, `highshelf/2` and `peak/2`, at `hz:` with `q:` and `db:`, `mode/2`, a resonator struck by its input at `hz:`, ringing at `level:` and fading 60 dB over `fade:` seconds, `wind_bands/2`, `delay/2`, and `dc_block/1`.
Shapes: `envelope/1` and `perc/1` are levels over time, and `envelope/2` and `perc/2` scale a sound by them.
Mixing: `mix/1` adds a list of sounds, and `gain/2` scales one.
A synth ends with `note_envelope/2`, shaping its sound by the note's envelope, or `rings/2`, ending it after `seconds:`.

# `air_jet`

A flute's air jet at the pitch `hz:`, blown at the pressure `breath:`, its sound taking `even:` of its square for the even harmonics.
`wander:` drifts the breath as a note holds, `catch:` lets it fall at a slur, `corner:` is the bore's corner in Hz, `tuned:` the breath at which the jet is in tune, and `lift:` makes high notes louder; each is 0 unless given.
`sound:` and `side:` are functions of the jet's sound and of the side of the edge it flows to, from 0 to 1, and the jet plays what they give added together.

# `bowed_string`

A bowed string at the MIDI `note:`, bowed at `speed:` and `force:`, reached over `takes:` seconds, at `position:` along it from the bridge, its speed swayed by `rosin:` times pink noise.

# `clamp`

`value`, held between `low` and `high`.

# `db`

The gain of a level in decibels.

# `dc_block`

A sound with any constant offset taken out.

# `delay`

A sound delayed by `seconds:`, which may change as it plays, up to `max:`.

# `envelope`

Segments from silence through each point, `{seconds, level}` straight, `{seconds, level, curve}` bent, or `{seconds, level, :exp}` exponential.

# `envelope`

A sound scaled by the level `envelope/1` gives for `points`.

# `follow`

One of the note's options as a sound, gliding to each new value the song gives over the option's `_slide` seconds.

# `gain`

A sound scaled by a level.

# `hz`

The frequency of a MIDI note.

# `impulse`

A single sample at the start of the note.

# `mix`

Sounds added together.

# `noise`

Noise, `:white` or `:pink`.

# `note_envelope`

A sound shaped by the note's envelope, from the options `envelope_attrs/1` declares.

# `partials`

Harmonics of the pitch `hz` at each of `ratios:`, with their `levels:` and starting `phases:` in radians; a level of 0 leaves its harmonic out.

# `perc`

A quick rise over `attack:` and a fall to silence over `release:`.

# `perc`

A sound scaled by the level `perc/1` gives for `opts`.

# `rings`

A sound that rings until it fades by itself, ending after `seconds:`.

# `select`

`then` where `condition` holds, and `otherwise` elsewhere.

# `time`

The seconds since the note started.

# `vibrato`

A vibrato's swing `depth:` deep at `hz:`, growing in from a quarter second after the note starts over 1.2 more, its depth drifting by about a third and its rate wandering about 6 percent, as a player's do.

# `wind_bands`

A wind's sound through peaks at mx's eight bands up to 3162 Hz, `gains:` eight in dB at each of pp, mf and ff, and `levels:` in dB at each, following `vel:`.

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*Consult [api-reference.md](api-reference.md) for complete listing*