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SOUNDSHAPER: CDP REFERENCE

THIN GROUP- thin spectrum by keeping or rejecting strongest partials


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SPECTRAL > FILTER > THIN >

SUMMARY
Thin spectrum by keeping (TRACE) or rejecting (SUPPRESS) the strongest partials, or by thinning randomly (SCATTER). The thinning is performed separately on each analysis window.

TRACE
Retain only the loudest N spectral components per analysis window

MODES
 1. Trace partials:  retain loudest N spectral components (see trace parameter)
 2. Trace and filter (high pass): retain loudest N spectral components above low freq and zero those below it.
 3. Trace and filter (low pass): retain loudest N spectral components below high freq and zero those above it.
 4. Trace and filter (band pass): retain loudest N spectral components between low freq and high freq and zero those outside the band.

OPTION

• Reverse filter: Reject channels inside the filter band and retain those outside.

PARAMETERS
 trace: Number of spectral components (channels), in order of loudness, to retain in each analysis window.
Range: 1-no. of chans (e.g. 1-1024)  T-V
 low freq:  Filter out all frequencies lower than this.
Range:  5-22050 Hz  T-V
 high freq: Filter out all frequencies higher than this.
Range:  5-22050 Hz  T-V


SUPPRESS
Suppress partials: reject the loudest N spectral components per analysis window

PARAMETERS
 suppress: Number of spectral components (channels) to reject in each analysis window.
Range: 1-no. of chans (e.g. 1-1024)  T-V


SCATTER
Thin spectrum randomly: keep N randomly chosen frequency blocks per analysis window

OPTIONS
• Randomize keep: Randomise number of blocks kept (1 to "keep" no.)
No normalisation: Turn off normalisation of resulting sound (default: normalise).

PARAMETERS
 keep: Number of randomly-chosen frequency blocks to retain in each analysis window.
Range: 1-no. of chans (e.g. 1-1024)  T-V
 block size:  Frequency range of blocks, rounded to multiple of channel bandwidth.
Range: 1 channel-11025 Hz; default 1 chan. bandwidth (e.g. 43.066 Hz.)  T-V


NOTES
These functions provide a 'ghost' of the sound, which often remains surprisingly coherent even with just a few partials retained. Scatter creates a granular effect in a continuous sound.
Trace
and Suppress can be used together to partition the sound in stages:

Firstly, B_0 is a copy of the source A_0.  B_1 [Trace] retains the 10 loudest components while A_1 [Suppress] rejects them. A_1 (the residue) is copied to C_1 and the process is repeated: C_2 [Trace] retains the next 10 loudest components while A_2 [Suppress] rejects them. A_2 is copied to D2 and D_3 [Trace] retains the remaining 10 loudest components. Thus B_1, C_2 and D_3 have respectively extracted the 30 loudest components in sets of 10.

Note that a trace function is also built into the processes BLUR+TRACE and TUNE.

© Ensemble Software and Composers Desktop Project 2014