An unhygienic macro for generating the standard template I use for instruments.

deftrack.clj

(defmacro deftrack

  "Defines an instrument with frequency, duration, volume, position and wet pre-defined.
  NB: these variables will shadow any instances in a wider scope.
  
  (deftrack simple [vibrato 3]
    (* (saw frequency) (sin-osc vibrato)) ; Signal
    (adsr))                               ; Envelope
  
  (simple :frequency 440 :position -1 :wet 1)
  (simple :frequency 220 :position 1 :duration 5.0 :vibrato 5.0)"

  [instrument extra-params oscillator envelope]

  `(definst ~instrument
     [~'frequency 440 ~'duration 1.0 ~'volume 1.0 ~'position 0.0 ~'wet 0.3 ~@extra-params]
     (-> ~oscillator                                                     ; Signal
         (~'* (env-gen ~envelope (line:kr 1 0 ~'duration) :action FREE)) ; Envelope
         (free-verb :mix (~'* 1/3 ~'wet) :room 0.1)                      ; Early reflections.
         (free-verb :mix ~'wet :room 0.7)                                ; Proper reverb
         (~'* ~'volume)                                                  ; Volume
         (pan2 ~'position))))                                            ; Panning