
Inverted parabolic envelope
Type : envellope generation References : Posted by James McCartney Code : dur = duration in samples
midlevel = amplitude at midpoint
beglevel = beginning and ending level (typically zero)
amp = midlevel  beglevel;
rdur = 1.0 / dur;
rdur2 = rdur * rdur;
level = beglevel;
slope = 4.0 * amp * (rdur  rdur2);
curve = 8.0 * amp * rdur2;
...
for (i=0; i
level += slope;
slope += curve;
} 
Comments
Added on : 11/04/02 by krakengore[ AT ]libero[ DOT ]it Comment : This parabola approximation seems more like a linear than a parab/expo envelope... or i'm mistaking something but i tryed everything and is only linear.
Added on : 13/04/02 by ex0r0x0r[ AT ]hotmail[ DOT ]com Comment : slope is linear, but 'slope' is a function of 'curve'. If you imagine you threw a ball upwards, think of 'curve' as the gravity, 'slope' as the vertical velocity, and 'level' as the vertical displacement.
Added on : 17/01/05 by asynth(at)io(dot)com Comment : This is not an approximation of a parabola, it IS a parabola.
This entry has become corrupted since it was first posted. Should be:
for (i=0; i<dur; ++i) {
out = level;
level += slope;
slope += curve;
}

Add your own comment
Comments are displayed in fixed width, no HTML code allowed! 



