Standard Builtin

(use std/builtin)

`builtin/slew!`

Smooths the input signal using a lowpass filter.

in
time, slew time, in seconds

  (b-lowpass! :in in
              :q 0.2
              :freq (/ 5.0
                       (* (* 2 PI) time)))

`builtin/pitch-shift!`

Modifies the pitch of the input signal using granular synthesis.

in
target-pitch, pitch difference, in semitones, between dry and wet signal
grain-size, grain size, in milliseconds

  (* 0.1
     (grains! :size grain-size
              :density (/ (* 10.0 1000.0) grain-size)
              :speed (exp2 (/ target-pitch 12.0))
              :position (< target-pitch 0.0)
              :in in))

`builtin/comb!`

Adds a delay to the dry signal.

in
delay, delay, in seconds, between dry and wet signal
depth, mix, in range [0; 1], between the dry and wet signal
polarity, sets the sign of the wet signal

  (+ (* in (- 1 (* 0.5 depth)))
     (* (* polarity (delay! in delay)) (* 0.5 depth)))

`builtin/fm!`

FM synthesis

carrier-freq, carrier frequency, in hertz
mod-freq, modulator frequency, in hertz
mod-index, modulation index

  (sine! (+ carrier-freq
            (* (* mod-freq mod-index)
               (sine! mod-freq))))