shepard-tones.lhs

shepard tones (alberto de campo)

> let { indxs n l r = let i = (r - l) / n 
>                     in [l, l + i .. r - i]
>     ; hanningWindow n = 
>           let { lp = pi * (-0.5)
>               ; rp = lp + 2 * pi 
>               ; hf i = sin i * 0.5 + 0.5 }
>           in map hf (indxs n lp rp)
>     ; square x = x * x
>     ; ampTable = map square (hanningWindow 1024) 
>     ; amp_f i = (0.5 ** i) * 20000
>     ; freqTable = map amp_f (indxs 1024 0 10)
>     ; ratescale = 1024 / 44100 / 10
>     ; rate = 0.1
>     ; ph = phasor ar 0 (rate * ratescale) 0 1024 0
>     ; phases = mce (map (\n -> n * 0.1 * 1024 + ph) [0..9])
>     ; freqs = bufRdC 1 ar 1 phases Loop
>     ; amps = bufRdC 1 ar 2 phases Loop
>     ; tone = mix (sinOsc ar freqs 0 * amps) * 0.1 }
> in withSC3 (\fd -> do { async fd (b_alloc 1 1024 1)
>                       ; async fd (b_alloc 2 1024 1)
>                       ; send fd (b_setn1 1 0 freqTable)
>                       ; send fd (b_setn1 2 0 ampTable)
>                       ; audition (out 0 tone) })

{ var ampTable = Signal.hanningWindow(1024).squared
; var amp_f = { arg i; 0.5 ** i * 20000 }
; var freqTable = Signal.newClear(1024).waveFill(amp_f, 0, 10)
; var b1 = Buffer.loadCollection(s, freqTable)
; var b2 = Buffer.loadCollection(s, ampTable)
; var ratescale = 1024 / 44100 / 10
; var rate = 0.1
; var ph = Phasor.ar(0, rate * ratescale, 0, 1024, 0)
; var phases = (0..9) * 0.1 * 1024 + ph
; var freqs = BufRd.ar(1, b1.bufnum, phases)
; var amps = BufRd.ar(1, b2.bufnum, phases)
; var tone = Mix.ar(SinOsc.ar(freqs) * amps) * 0.1 
; Out.ar(0, tone)}.play