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SOUNDSHAPER: CDP REFERENCE

INVERTSPEC - invert spectrum around a given frequency


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SPECTRAL > FREQ/PITCH > INVERTSPEC >

SUMMARY
Invert spectrum around a given frequency. Partials are inverted around a given frequency: if they were originally above the frequency, they appear an equivalent amount below it, and vice versa.

PARAMETERS
 invert Frequency (f) around which to invert the spectrum.
It is assumed that frequencies originally below this (f-n) are placed the same amount above it (f+n), while those originally above it (f+n) are placed the same amount below (f-n). [The actual operation has not been documented.]
Range:  c.44 (1 chan. bandwidth) - c.20000 Hz.

NOTES
Inverting the spectrum will turn high frequencies (such as high harmonics) into low ones and vice versa. You can also expect a harmonic sound to become inharmonic. If a high invert_frequency figure is given, the lowest of the original frequencies may well disappear, being beyond the Nyquist frequency (and our hearing). Equally, if a very low figure is given, high frequency data is inverted too low to be heard (or to be resolved within the channel bandwidth). Soundshaper's data range is therefore more than generous for most purposes, despite being less than the full legal CDP range.

As the resultant sound is often a bit "thin", it's worth carrying out a few inversions at different frequencies (e.g. 1k, 2k and 4k) and mixing the result.

© Ensemble Software and Composers Desktop Project 2012