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.
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