1.5 KiB
Bifurcator instrument editor
Bifurcator instrument editor consists of these macros:
- Volume: volume sequence.
- Arpeggio: pitch sequence.
- Parametet: set parameter of logistic map function.
- Panning (left): output level for left channel.
- Panning (right): output level for right channel.
- Pitch: fine pitch.
- Load Value: changes the current output value.
audio generation description
Bifurcator uses logistic map iterations for sound generation. basically it runs the following function over and over:
r = (1 + (p / 65536)) * 2
x = (r * x) * (1 - x)
where x is the current output value and p is the "parameter".
by varying the parameter, the value of x may change drastically, producing a variety of sounds. the higher the parameter, the more "chaos" is present, effectively yielding noise.
the default parameter is 47360, which results in a square wave.
if the parameter is set to 0, there's no sound at all.
as the parameter approaches 32768, a decaying square wave is produced.
the square wave stops decaying past 32768 and becomes louder until the parameter hits ~47496 (r = 1 + sqrt(6)).
a second square wave one octave lower then starts appearing, until the parameter reaches ~51443 (r ≈ 3.56995). this is where chaos begins.
anything higher results in a total mess.
however, at ~59914 (r = 1 + sqrt(8)) you can hear a 33% pulse wave.
the importance of loading the value
you must load a value that isn't 0 in order to get sound. otherwise the function will always output 0.