Sound.SC3.Lang.Control.Pitch

SC3 pitch model implementation.

Pitched

class Pitched p where

Pitched values, minimal definition is midinote.

 midinote (defaultPitch {degree = 5}) == 69
 freq (defaultPitch {degree = 5,detune = 10}) == 440 + 10

Methods

midinote :: p -> Double

freq :: p -> Double

Instances

Pitched Pitch

Pitch

data Pitch

The supercollider language pitch model is organised as a tree with three separate layers, and is designed to allow separate processes to manipulate aspects of the model independently.

The haskell variant implements Pitch as a labeled data type, with a default value such that scale degree 5 is the A above middle C.

 freq (defaultPitch {degree = 5}) == 440

The note is given as a degree, with a modal transposition, indexing a scale interpreted relative to an equally tempered octave divided into the indicated number of steps.

The midinote is derived from the note by adding the indicated root, octave and gamut transpositions.

The frequency is derived by a chromatic transposition of the midinote, with a harmonic multiplier.

 let {p = defaultPitch
     ;n = p {stepsPerOctave = 12
            ,scale = [0,2,4,5,7,9,11]
            ,degree = 0
            ,mtranspose = 5}
     ;m = n {root = 0
            ,octave = 5
            ,gtranspose = 0}
     ;f = m {ctranspose = 0
            ,harmonic = 1}}
 in (note n,midinote m,freq f) == (9,69,440)

By editing the values of aspects of a pitch, processes can cooperate. Below one process controls the note by editing the modal transposition, a second edits the octave.

 let {edit_mtranspose p d = p {mtranspose = mtranspose p + d}
     ;edit_octave p o = p {octave = octave p + o}
     ;p' = repeat defaultPitch
     ;q = zipWith edit_mtranspose p' [0,2,4,3,5]
     ;r = zipWith edit_octave q [0,-1,0,1,0]
     ;f = map midinote}
 in (f q,f r) == ([60,64,67,65,69],[60,52,67,77,69])

Constructors

Pitch

Fields

mtranspose :: Double

gtranspose :: Double

ctranspose :: Double

octave :: Double

root :: Double

scale :: [Double]

degree :: Double

stepsPerOctave :: Double

detune :: Double

harmonic :: Double

freq' :: Maybe Double

midinote' :: Maybe Double

note' :: Maybe Double

Instances

Eq Pitch

Show Pitch

Pitched Pitch

defaultPitch :: Pitch

A default Pitch value of middle C given as degree 0 of a C major scale.

 let {p = defaultPitch
     ;r = ([0,2,4,5,7,9,11],12,0,5,0)}
 in (scale p,stepsPerOctave p,root p,octave p,degree p) == r

note :: Pitch -> Double

Calculate note field.

 note (defaultPitch {degree = 5}) == 9

Optional

type T616 a b c = (a, a, a, a, a, a, b, c, c, c, c, c, c)

Tuple in 6-1-6 arrangement.

type OptPitch = T616 (Maybe Double) (Maybe [Double]) (Maybe Double)

Pitch represented as tuple of optional values.

optPitch :: OptPitch -> Pitch

Transform OptPitch to Pitch.