CDP Sound Examples – GRANULATION

Rhythmic granulations

SOURCE SOUND

Granulated vocal phrase
(from balsam.wav)

TRANSFORMATIONS

cycling intergrain expansion
cycling expansion on each grain
cycling pitch transpositions

DESCRIPTION
~ CDP Function: GRAIN RERHYTHM & REPITCH ~

• To provide a suitable source for this operation, a vocal phrase was granulated with GRAIN GRANULATE using the time-varying file exgrnden.brk in which the grains let longer in the middle. This produced balsamgrn.wav, used as the source for the GRAIN RERHYTHM process.
• Using GRAIN COUNT, it was determined that a gate of 0.05 resulted in about 10 grains, which pretty much matched what was heard in balsamgrn.wav. This value was therefore used in the subsequent operations.
• The GRAIN RERHYTHM process uses a time-varying text file of multipliers (exgrn1.txt) which decrease or increase the time between grain onsets. The sequence of times here increase in duration, which results in a gradual slowing down of the grains.
• In Mode 1 of GRAIN RERHYTHM, we move through the grains, applying the time multipliers, cycling round to the first time multiplier until we run out of grains. This produces exgrn1rr.wav. It all happens very quickly, and the slowing down is subtle.
• In Mode 2 of GRAIN RERHYTHM, we repeat the sequence of time multipliers on each grain, thus producing a series of slowings down which are much more perceptible This creates exgrn2rr.wav.
• Finally, we play with it some more by applying a sequence of transposition multipliers to the grains with GRAIN REPITCH. We go back to exgrn1rr.wav as our source so that we start with an already rhythmically massaged file. We use Mode 2 to produce more grains. Now the grains also jump up and down in the output soundfile exgrn1rrtrans.wav, moving tighter and then opening out again.

Additional Information

PARAMETER SETTINGS
(Click on image to view fullsize)

KEY POINTS

• These sounds illustrate a number of the GRAIN functions, by which we can create a range of specific effects on a grainy input. These complement the main granulation processing of BRASSAGE and GRAINMILL.
• GRAIN GRANULATE is used to create a grainy starting point for the other operations.
• The gate parameter is set such that the count of grains is more or less the same as the number of grains perceived when listening to the sound. If too few are identified, the new function fails to alter many of the grains.
• This example uses three of the GRAIN functions, chaining the output of the previous as the input to the next.


• Omitting the last grain often avoids having a click at the end.

SUPPLEMENTARY FILES USED

BREAKPOINT FILE, time grain_length (time varying granulation)

[exgrnden.brk]
0.0	0.1
1.0	0.5 (grains are longer towards the middle of the file)
1.9	0.2

TEXT FILE OF TIME MULTIPLIERS (time-gaps between grains are altered)

[exgrn1.txt]
0.2 0.8 1.8 3.4  (the gaps get longer, the sound more 'halting')

TEXT FILE OF TRANSPOSITIONS (sequence of semitone transpositions)

[exgrn1tr.txt]
-3 3 -2 2 -1 1 0 1 -1 2 -2 (wider -> narrower -> wider)