【TidalCycles】3度上の音を再生する

はじめに

TidalCyclesで3度上、5度下などの音を重ねたいと思ったときにいいやり方がわからなかったので、degreesUp関数を作ってみました。

degreesUp関数の実装

以下のコードをBootTidal.hsに追記して、TidalCyclesを再起動すればdegreesUp関数が使えるようになるかと思います

BootTidal.hs

:{
majorC :: Num a => [a]
majorC = [0,2,4,5,7,9,11]

majorKey :: (Eq a1, Data.String.IsString a1, Num a2) => a1 -> [a2]
majorKey key
  | elem key ["c"] = majorC
  | elem key ["cs","df"] = map (+1) majorC
  | elem key ["d"] = map (+2) majorC
  | elem key ["ds", "ef"] = map (+3) majorC
  | elem key ["e"] = map (+4) majorC
  | elem key ["f"] = map (+5) majorC
  | elem key ["fs", "gf"] = map (+6) majorC
  | elem key ["g"] = map (+7) majorC
  | elem key ["gs", "af"] = map (+8) majorC
  | elem key ["gs", "af"] = map (+9) majorC
  | elem key ["a"] = map (+10) majorC
  | elem key ["as", "bf"] = map (+11) majorC
  | elem key ["b"] = map (+12) majorC
  | otherwise = error "invalid key name!"

degreesUp :: (Num a, Eq a1, Data.String.IsString a1) => a1 -> Int -> Int -> a
degreesUp key degree n =
  noteInScale (majorScale) (degree+elemScaleIndex n)
  where majorScale = majorKey key
        octave s x = x `div` length s
        noteInScale s x = (s !! (mod x (length s))) + fromIntegral (12 * octave s x)
        elemScaleIndex n
          | isJust(elemIndex (mod n 12) majorScale) = fromJust(elemIndex (mod n 12) majorScale) + (length majorScale)*(n `div` 12)
          | otherwise = elemScaleIndex (n+1)

degreesUp' :: (Num a, Eq a1, Data.String.IsString a1) => a1 -> Int -> Int -> a
degreesUp' key degree n
  | degree==0  = degreesUp key 0 n
  | degree>0   = degreesUp key (degree-1) n
  | degree<0   = degreesUp key (degree+1) n
:}

degreesUp関数の使い方

例えば、キーがCで3度上の音を重ねたい場合は以下のようにすると実現できます。

live.tidal

do
  let
    nPat = "[c4|d6|e5|f5|g4|a5|b4]*8"
    degree = 3
  d1
    $ stack[
    s "superpiano*8"
    # n nPat
    ,
    s "superpiano*8"
    # n (degreesUp' "c" degree <$> nPat)
    ]

いろいろな度数で試してみるとこんな感じになります。