Vibrato Pedal. Implements a pitch bend via an LFO’d delay. Expression…

… control increases the effect amount with signal amplitude.

lib/Engine_Pedalboard.sc

@@ -33,6 +33,7 @@ Engine_Pedalboard : CroneEngine {
       SustainPedal,
       TremoloPedal,
       TunerPedal,
+      VibratoPedal,
     ];
     allPedalIds = List.new;
     pedalDetails = Dictionary.new;

lib/fx/Vibrato.sc

@@ -0,0 +1,26 @@
+VibratoPedal : Pedal {
+  *id { ^\vibrato; }
+
+  *fxArguments { ^[\rate, \depth, \expression]; }
+
+  *fxDef {^{|wet|
+    var expression, envelopeFollower, envMultiplier, rate, depth, mul, minRate, maxDepth, maxDelay;
+    // Track the amplitude, so we vibrato more and faster when the signal is louder
+    envelopeFollower = Lag.ar(EnvFollow.ar((wet * 6).clip(-1, 1), 0.999), 0.14);
+    // Expression scales how much the envelope influences our vibrato
+    expression = \expression.kr(0.5);
+    envMultiplier = (1 - expression) + (envelopeFollower * expression);
+    // Delay the vibrato until after the attack  portion of a typical envelope
+    envMultiplier = DelayN.ar(envMultiplier, 0.1, 0.07);
+    // Rate is how many vibratos per second
+    minRate = 0.75;
+    rate = LinExp.ar(\rate.kr(0.5) * envMultiplier, 0, 1, minRate, 60);
+    // Depth is pitch bend range in cents
+    maxDepth = 30;
+    depth = LinExp.ar(\depth.kr(0.5) * envMultiplier, 0, 1, 3.3, maxDepth);
+    // Mul calculates the amplitude of the LFO for our delay to achieve the given rate and depth
+    mul = ((2 ** (depth * 1200.reciprocal)) - 1)/(4 * rate);
+    maxDelay = (((2 ** (maxDepth * 1200.reciprocal)) - 1)/(4 * minRate)) * 2.5;
+    wet = DelayC.ar(wet, maxDelay, SinOsc.ar(rate, 2, mul, mul + ControlRate.ir.reciprocal));
+  }}
+}

lib/ui/board.lua

@@ -21,6 +21,7 @@ local pedal_classes = {
   include("lib/ui/pedals/sustain"),
   include("lib/ui/pedals/bitcrusher"),
   include("lib/ui/pedals/pitch_shifter"),
+  include("lib/ui/pedals/vibrato"),
   include("lib/ui/pedals/auto_wah"),
   include("lib/ui/pedals/equalizer"),
   include("lib/ui/pedals/tuner"),

lib/ui/pedals/vibrato.lua

@@ -0,0 +1,62 @@
+--- VibratoPedal
+-- @classmod VibratoPedal
+
+local UI = require "ui"
+local Pedal = include("lib/ui/pedals/pedal")
+local Controlspecs = include("lib/ui/util/controlspecs")
+
+local VibratoPedal = Pedal:new()
+-- Must match this pedal's .sc file's *id
+VibratoPedal.id = "vibrato"
+
+function VibratoPedal:new(bypass_by_default)
+  local i = Pedal:new(bypass_by_default)
+  setmetatable(i, self)
+  self.__index = self
+
+  i.sections = {
+    {"Rate & Depth", "Expression"},
+    i:_default_section(),
+  }
+  i:_complete_initialization()
+
+  return i
+end
+
+function VibratoPedal:name(short)
+  return short and "VIBE" or "Vibrato"
+end
+
+function VibratoPedal.params()
+  local id_prefix = VibratoPedal.id
+
+  local rate_control = {
+    id = id_prefix .. "_rate",
+    name = "Rate",
+    type = "control",
+    controlspec = Controlspecs.MIX,
+  }
+  local depth_control = {
+    id = id_prefix .. "_depth",
+    name = "Depth",
+    type = "control",
+    controlspec = Controlspecs.MIX,
+  }
+  local expression_control = {
+    id = id_prefix .. "_expression",
+    name = "Expression",
+    type = "control",
+    controlspec = Controlspecs.MIX,
+  }
+
+  -- Default mix of 100%
+  local default_params = Pedal._default_params(id_prefix)
+  default_params[1][2].controlspec = Controlspecs.mix(100)
+
+  return {
+    {{rate_control, depth_control}, {expression_control}},
+    default_params,
+  }
+end
+
+return VibratoPedal