gendy1.help.lhs

gendy1 rate ampDist durDist adParam ddParam minFreq maxFreq 
       ampScale durScale initCPs kNum

An implementation of the dynamic stochastic synthesis generator
conceived by Iannis Xenakis and described in Formalized Music
(1992, Stuyvesant, NY: Pendragon Press) chapter 9 (pp 246-254) and
chapters 13 and 14 (pp 289-322). The BASIC program in the book was
written by Marie-Helene Serra so I think it helpful to credit her
too.

ampdist - Choice of probability distribution for the next
          perturbation of the amplitude of a control point.

The distributions are (adapted from the GENDYN program in
Formalized Music):

  0- LINEAR
  1- CAUCHY
  2- LOGIST
  3- HYPERBCOS
  4- ARCSINE
  5- EXPON
  6- SINUS

Where the sinus (Xenakis' name) is in this implementation taken as
sampling from a third party oscillator. See example below.

durdist - Choice of distribution for the perturbation of the
          current inter control point duration.

adparam - A parameter for the shape of the amplitude probability
          distribution, requires values in the range 0.0001 to 1
          (there are safety checks in the code so don't worry too
          much if you want to modulate.)

ddparam - A parameter for the shape of the duration probability
          distribution, requires values in the range 0.0001 to 1

minfreq - Minimum allowed frequency of oscillation for the Gendy1
          oscillator, so gives the largest period the duration is
          allowed to take on.

maxfreq - Maximum allowed frequency of oscillation for the Gendy1
          oscillator, so gives the smallest period the duration is
          allowed to take on.

ampscale - Normally 0.0 to 1.0, multiplier for the distribution's
           delta value for amplitude. An ampscale of 1.0 allows the
           full range of -1 to 1 for a change of amplitude.

durscale - Normally 0.0 to 1.0, multiplier for the distribution's
           delta value for duration. An ampscale of 1.0 allows the
           full range of -1 to 1 for a change of duration.

initCPs - Initialise the number of control points in the
          memory. Xenakis specifies 12. There would be this number
          of control points per cycle of the oscillator, though the
          oscillator's period will constantly change due to the
          duration distribution.

knum - Current number of utilised control points, allows
       modulation.


sclang defaults: ampdist=1, durdist=1, adparam=1.0, ddparam=1.0,
minfreq=440, maxfreq=660, ampscale= 0.5, durscale=0.5, initCPs= 12,
knum=12.

> let g = gendy1 AR 1 1 1 1 440 660 0.5 0.5 12 12
> in audition (out 0 (pan2 g 0 0.15))

Wandering bass

> let g = gendy1 AR 1 1 1.0 1.0 30 100 0.3 0.05 5 5
> in audition (out 0 (pan2 g 0 0.15))

Play me	

> let { x = mouseX KR 100 1000 Exponential 0.1
>     ; g = gendy1 AR 1 1 1.0 1.0 30 100 0.3 0.05 5 5 }
> in audition (out 0 (pan2 (rlpf g 500 0.3 * 0.2) 0 0.25))

Scream!

> let { x = mouseX KR 220 440 Exponential 0.1
>     ; y = mouseY KR 0.0 1.0 Linear 0.1 }
> in audition (out 0 (pan2 (gendy1 AR 2 3 1 1 x (8 * x) y y 7 7) 0.0 0.3))

1 CP = random noise

> let g = gendy1 AR 1 1 1 1 440 660 0.5 0.5 1 1
> in audition (out 0 (pan2 g 0 0.15))

2 CPs = an oscillator

> let g = gendy1 AR 1 1 1 1 440 660 0.5 0.5 2 2 
> in audition (out 0 (pan2 g 0 0.15))

Used as an LFO

> let { ad = sinOsc KR 0.10 0 * 0.49 + 0.51
>     ; dd = sinOsc KR 0.13 0 * 0.49 + 0.51
>     ; as = sinOsc KR 0.17 0 * 0.49 + 0.51
>     ; ds = sinOsc KR 0.19 0 * 0.49 + 0.51
>     ; g = gendy1 KR 2 4 ad dd 3.4 3.5 as ds 10 10 }
> in audition (out 0 (pan2 (sinOsc AR (g * 50 + 350) 0) 0.0 0.3))

Wasp

> let ad = sinOsc KR 0.1 0 * 0.1 + 0.9
> in audition (out 0 (pan2 (gendy1 AR 0 0 ad 1.0 50 1000 1 0.005 12 12) 0.0 0.2))

Modulate distributions. Change of pitch as distributions change
the duration structure and spectrum

> let { x = mouseX KR 0 7 Linear 0.1
>     ; y = mouseY KR 0 7 Linear 0.1
>     ; g = gendy1 AR x y 1 1 440 660 0.5 0.5 12 12 }
> in audition (out 0 (pan2 g 0 0.2))

Modulate number of CPs.

> let { x = mouseX KR 1 13 Linear 0.1
>     ; g = gendy1 AR 1 1 1 1 440 660 0.5 0.5 12 x }
> in audition (out 0 (pan2 g 0 0.2))

Self modulation.

> let { x = mouseX KR 1   13 Linear 0.1
>     ; y = mouseY KR 0.1 10 Linear 0.1
>     ; g0 = gendy1 AR 5 4 0.3 0.7 0.1 y 1.0 1.0 5 5
>     ; g1 = gendy1 AR 1 1 1 1 440 (g0 * 500 + 600) 0.5 0.5 12 x }
> in audition (out 0 (pan2 g1 0 0.2))

Use SINUS to track any oscillator and take CP positions from it use
adParam and ddParam as the inputs to sample.

> let { p = lfPulse KR 100 0 0.4
>     ; s = sinOsc KR 30 0 * 0.5
>     ; g = gendy1 AR 6 6 p s 440 660 0.5 0.5 12 12 }
> in audition (out 0 (pan2 g 0 0.2))

Near the corners are interesting.

> let { x = mouseX KR 0 200 Linear 0.1
>     ; y = mouseY KR 0 200 Linear 0.1
>     ; p = lfPulse KR x 0 0.4
>     ; s = sinOsc KR y 0 * 0.5
>     ; g = gendy1 AR 6 6 p s 440 660 0.5 0.5 12 12 }
> in audition (out 0 (pan2 g 0 0.2))

Texture

> let node = do { f  <- rand 130 160.3
>               ; r0 <- rand 0 6
>               ; r1 <- rand 0 6
>               ; l  <- rand (-1) 1
>               ; let { ad = sinOsc KR 0.10 0 * 0.49 + 0.51
>                     ; dd = sinOsc KR 0.13 0 * 0.49 + 0.51
>                     ; as = sinOsc KR 0.17 0 * 0.49 + 0.51
>                     ; ds = sinOsc KR 0.19 0 * 0.49 + 0.51
>                     ; g = gendy1 AR r0 r1 ad dd f f as ds 12 12
>                     ; o = sinOsc AR (g * 200 + 400) 0 }
>                 in return (pan2 o l 0.1) }
> in do { m <- replicateM 9 node
>       ; audition (out 0 (mix (mce m))) }

Try durscale 10.0 and 0.0 too.

> let { x = mouseX KR 10 700 Linear 0.1
>     ; y = mouseY KR 50 1000 Linear 0.1
>     ; g = gendy1 AR 2 3 1 1 1 x 0.5 0.1 10 10 }
> in audition (out 0 (pan2 (combN (resonz g y 0.1) 0.1 0.1 5) 0.0 0.6))