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SOUNDSHAPER: CDP REFERENCE

SPECTRAL UTILITIES


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SPECTRAL
SPEC UTILS
pitch altharms; spec
bare/cut/gain/gate

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SPECTRAL > UTILS >

SUMMARY
A group of spectral utilities to remove non-harmonic data (SPECBARE), remove alternate harmonics (ALTHMCS); cut (SPECCUT) or alter the level (SPECGAIN) in a spectral file, or remove low-level signal (SPECGATE).

SPECBARE
Zeroes the data in channels which do not contain harmonics. It retains harmonic partials only, using a pitch data file (Infile 2: .frq) as reference. Normally, the pitch file would be extracted from the same source.
(In Soundshaper, when Infile 2 is requested, click on the same cell as Infile 1, and it will be converted automatically.)


PARAMETERS: none

OPTION:
• More body in the resulting spectrum.
 
NOTES
For more creative applications, the pitch file could come from another source; this would retain such of File 2's pitch that was already in File 1 (if any). The two files must be the same length.
When tried with Infile1: speech and Infile2: Piano A440, the speech was indeed filtered to A440 and its harmonics, without becoming strongly pitched.


ALTHMCS (CDP: pitch altharms)
Deletes alternate harmonics in a sound. The process requires a pitch data file (Infile 2: .frq) as reference. Normally, this would be extracted from the same source.
(In Soundshaper, when Infile 2 is requested, click on the same cell as Infile 1, and it will be converted automatically.)

MODES:
 1. Delete odd harmonics
 2. Delete even harmonics

PARAMETERS
: none

OPTION:
•  Alternative spectral reconstruction (no further information).
 
NOTES
ALTHMCS includes the SpecBare process; once it has removed non-harmonic data, it can delete either odd or even harmonics, depending on the mode.

SPECCUT
Extract and keep a segment of a spectral file at the times specified.

PARAMETERS
:
  start: time in infile where cut segment begins.
    Range: 0 - filelength-1 window (secs)
  end: time in infile where cut segment ends.
    Range: 1 window - filelength (secs)

NOTES
The length of a spectral file is not exactly the same as its time-domain counterpart. If timing precision is critical, it may be better to make the cut in the time-domain and convert the result to the frequency domain or send it to a spectral process.

SPECGAIN
Amplify or attenuate the spectrum.

PARAMETER
:
  gain: Attenuate (<1) or increase (>1) the amplitude.  
    Range: 0-1-10000; T-V
 
NOTES
Amplifying a poor signal will boost noise content in the weakest spectral channels. It may be worth applying SPECGATE or TRACE first, to eliminate data in these channels.

SPECGATE
Eliminate channel data below a threshold amplitude: cuts out low level signal in each frequency channel over time.


PARAMETER:
  threshold: lowest acceptable amplitude level
    Range: 0-1; T-V

 
NOTES
SPECGATE can clean up a signal by removing the low-level signal below a given level across all channels.

© Ensemble Software and Composers Desktop Project 2014