322 lines
7.7 KiB
Racket
322 lines
7.7 KiB
Racket
#lang scribble/manual
|
|
@(require (for-label racket))
|
|
|
|
@title{Gendy1}
|
|
Dynamic stochastic synthesis generator.@section{related}
|
|
Classes/Gendy2, Classes/Gendy3
|
|
@section{categories}
|
|
UGens>Generators>Stochastic
|
|
|
|
|
|
@section{description}
|
|
|
|
|
|
An implementation of the dynamic stochastic synthesis generator conceived
|
|
by Iannis Xenakis and described in emphasis::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.
|
|
|
|
The program code has been adapted to avoid infinities in the probability
|
|
distribution functions.
|
|
|
|
The distributions are hard-coded in C but there is an option to have new
|
|
amplitude or time breakpoints sampled from a continuous controller input.
|
|
|
|
@section{subsection}
|
|
Technical notes
|
|
X's plan as described in chapter 13 allows the 12 segments in the period to be successively modified with each new period.
|
|
Yet the period is allowed to vary as the sum of the segment durations, as figure 1 demonstrates.
|
|
We can setup some memory of n (conventionally 12) points, or even simply vary successively a single point's ordinate and
|
|
duration. There are thus various schemes available to us. In one, fix period T and only move the (ti, Ei) within the period. In another, have a memory of 12 segments but allow continuous modification of the inter point intervals and the amplitudes.
|
|
In yet another, just have one point and random walk its amplitude and duration based on the probability distribution.
|
|
In this implementation I allow the user to initialise a certain number of memory points which is up to them.
|
|
To restrict the period to be unchanging, you must set rate variation to zero (dscale=0).
|
|
|
|
SuperCollider implementation by Nick Collins.
|
|
|
|
|
|
@section{classmethods}
|
|
|
|
|
|
@section{method}
|
|
ar, kr
|
|
|
|
@section{argument}
|
|
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):
|
|
|
|
@section{table}
|
|
|
|
## 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.
|
|
|
|
|
|
@section{argument}
|
|
durdist
|
|
|
|
Choice of distribution for the perturbation of the current inter
|
|
control point duration.
|
|
|
|
|
|
@section{argument}
|
|
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!).
|
|
|
|
|
|
@section{argument}
|
|
ddparam
|
|
|
|
A parameter for the shape of the duration probability
|
|
distribution, requires values in the range 0.0001 to 1.
|
|
|
|
|
|
@section{argument}
|
|
minfreq
|
|
|
|
Minimum allowed frequency of oscillation for the Gendy1
|
|
oscillator, so gives the largest period the duration is allowed
|
|
to take on.
|
|
|
|
|
|
@section{argument}
|
|
maxfreq
|
|
|
|
Maximum allowed frequency of oscillation for the Gendy1
|
|
oscillator, so gives the smallest period the duration is allowed
|
|
to take on.
|
|
|
|
|
|
@section{argument}
|
|
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.
|
|
|
|
|
|
@section{argument}
|
|
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.
|
|
|
|
|
|
@section{argument}
|
|
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.
|
|
|
|
|
|
@section{argument}
|
|
knum
|
|
|
|
Current number of utilised control points, allows modulation.
|
|
|
|
@section{argument}
|
|
mul
|
|
|
|
@section{argument}
|
|
add
|
|
|
|
@section{discussion}
|
|
|
|
All parameters can be modulated at control rate except for
|
|
@racketblock[initCPs:: which is used only at initialisation.
|
|
|
|
]
|
|
@section{Examples}
|
|
|
|
|
|
@section{warning}
|
|
|
|
if you have lots of CPs and you have fast frequencies, the CPU cost goes up a lot because a new CP move happens every sample!
|
|
::
|
|
|
|
|
|
@racketblock[
|
|
//defaults
|
|
{Pan2.ar(Gendy1.ar)}.play
|
|
|
|
//wandering bass/ powerline
|
|
{Pan2.ar(Gendy1.ar(1,1,1.0,1.0,30,100,0.3,0.05,5))}.play
|
|
|
|
//play me
|
|
{Pan2.ar(RLPF.ar(Gendy1.ar(2,3,minfreq:20,maxfreq:MouseX.kr(100,1000),durscale:0.0,initCPs:40),500,0.3,0.2),0.0)}.play
|
|
|
|
//scream! - careful with your ears for this one!
|
|
(
|
|
{
|
|
var mx, my;
|
|
|
|
mx= MouseX.kr(220,440);
|
|
my= MouseY.kr(0.0,1.0);
|
|
|
|
Pan2.ar(Gendy1.ar(2,3,1,1,minfreq:mx, maxfreq:8*mx, ampscale:my, durscale:my, initCPs:7, mul:0.3), 0.0)
|
|
}.play
|
|
)
|
|
|
|
|
|
//1 CP = random noise effect
|
|
{Pan2.ar(Gendy1.ar(initCPs:1))}.play
|
|
|
|
//2 CPs = suudenly an oscillator (though a fast modulating one here)
|
|
{Pan2.ar(Gendy1.ar(initCPs:2))}.play
|
|
|
|
|
|
//used as an LFO
|
|
(
|
|
{
|
|
Pan2.ar(
|
|
SinOsc.ar(
|
|
Gendy1.kr(2, 4,
|
|
SinOsc.kr(0.1,0,0.49,0.51),
|
|
SinOsc.kr(0.13,0,0.49,0.51),
|
|
3.4, 3.5,
|
|
SinOsc.kr(0.17,0,0.49,0.51),
|
|
SinOsc.kr(0.19,0,0.49,0.51),
|
|
10,10,50, 350),
|
|
0, 0.3),
|
|
0.0)
|
|
}.play
|
|
)
|
|
|
|
//wasp
|
|
{Pan2.ar(Gendy1.ar(0, 0, SinOsc.kr(0.1, 0, 0.1, 0.9),1.0, 50,1000, 1,0.005, 12, 12, 0.2), 0.0)}.play
|
|
|
|
|
|
//modulate distributions
|
|
//change of pitch as distributions change the duration structure and spectrum
|
|
{Pan2.ar(Gendy1.ar(MouseX.kr(0,7),MouseY.kr(0,7),mul:0.2), 0.0)}.play
|
|
|
|
|
|
//modulate num of CPs
|
|
{Pan2.ar(Gendy1.ar(knum:MouseX.kr(1,13),mul:0.2), 0.0)}.play
|
|
|
|
|
|
(//Gendy into Gendy...with cartoon side effects
|
|
{Pan2.ar(Gendy1.ar(
|
|
maxfreq:Gendy1.kr(5,4,0.3, 0.7, 0.1, MouseY.kr(0.1,10), 1.0, 1.0, 5,5, 500, 600),
|
|
knum:MouseX.kr(1,13),mul:0.2), 0.0)
|
|
}.play
|
|
)
|
|
|
|
//use SINUS to track any oscillator and take CP positions from it, use adparam and ddparam as the inputs to sample
|
|
{Pan2.ar(Gendy1.ar(6,6,LFPulse.kr(100, 0, 0.4, 1.0), SinOsc.kr(30, 0, 0.5),mul:0.2), 0.0)}.play
|
|
|
|
|
|
//try out near the corners especially
|
|
(
|
|
{Pan2.ar(Gendy1.ar(6,6,LFPulse.kr(MouseX.kr(0,200), 0, 0.4, 1.0),
|
|
SinOsc.kr(MouseY.kr(0,200), 0, 0.5),mul:0.2), 0.0)}.play
|
|
)
|
|
|
|
//texture
|
|
(
|
|
{
|
|
Mix.fill(10,{
|
|
var freq;
|
|
|
|
freq= rrand(130,160.3);
|
|
Pan2.ar(SinOsc.ar(Gendy1.ar(6.rand,6.rand,SinOsc.kr(0.1,0,0.49,0.51),
|
|
SinOsc.kr(0.13,0,0.49,0.51),freq ,freq, SinOsc.kr(0.17,0,0.49,0.51),
|
|
SinOsc.kr(0.19,0,0.49,0.51), 12, 12, 200, 400), 0, 0.1), 1.0.rand2)
|
|
});
|
|
}.play
|
|
)
|
|
|
|
//wahhhhhhhh- try durscale 10.0 and 0.0 too
|
|
(
|
|
{Pan2.ar(
|
|
CombN.ar(
|
|
Resonz.ar(
|
|
Gendy1.ar(2,3,minfreq:1, maxfreq:MouseX.kr(10,700), durscale:0.1, initCPs:10),
|
|
MouseY.kr(50,1000), 0.1)
|
|
,0.1,0.1,5, 0.6
|
|
)
|
|
, 0.0)}.play
|
|
)
|
|
|
|
//overkill
|
|
(
|
|
{
|
|
var n;
|
|
n=10;
|
|
|
|
Mix.fill(n,{
|
|
var freq, numcps;
|
|
|
|
freq= rrand(130,160.3);
|
|
numcps= rrand(2,20);
|
|
Pan2.ar(Gendy1.ar(6.rand,6.rand,1.0.rand,1.0.rand,freq ,freq, 1.0.rand, 1.0.rand, numcps,
|
|
SinOsc.kr(exprand(0.02,0.2), 0, numcps/2, numcps/2), 0.5/(n.sqrt)), 1.0.rand2)
|
|
});
|
|
}.play
|
|
)
|
|
|
|
//another traffic moment
|
|
(
|
|
{
|
|
var n;
|
|
n=10;
|
|
|
|
Resonz.ar(
|
|
Mix.fill(n,{
|
|
var freq, numcps;
|
|
|
|
freq= rrand(50,560.3);
|
|
numcps= rrand(2,20);
|
|
Pan2.ar(Gendy1.ar(6.rand,6.rand,1.0.rand,1.0.rand,freq ,freq, 1.0.rand, 1.0.rand, numcps,
|
|
SinOsc.kr(exprand(0.02,0.2), 0, numcps/2, numcps/2), 0.5/(n.sqrt)), 1.0.rand2)
|
|
})
|
|
,MouseX.kr(100,2000), MouseY.kr(0.01,1.0))
|
|
;
|
|
}.play
|
|
)
|
|
|
|
(
|
|
{
|
|
var n;
|
|
n=15;
|
|
|
|
Out.ar(0,
|
|
Resonz.ar(
|
|
Mix.fill(n,{
|
|
var freq, numcps;
|
|
|
|
freq= rrand(330,460.3);
|
|
numcps= rrand(2,20);
|
|
Pan2.ar(Gendy1.ar(6.rand,6.rand,1.0.rand,1.0.rand,freq,MouseX.kr(freq,2*freq), 1.0.rand, 1.0.rand, numcps,
|
|
SinOsc.kr(exprand(0.02,0.2), 0, numcps/2, numcps/2), 0.5/(n.sqrt)), 1.0.rand2)
|
|
})
|
|
,MouseX.kr(100,2000), MouseY.kr(0.01,1.0))
|
|
)
|
|
|
|
}.play;
|
|
)
|
|
::
|
|
|
|
]
|
|
|
|
|