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SOUNDSHAPER: CDP REFERENCE

SHIFT - shift the spectral frequencies


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SPECTRAL > FREQ/PITCH > SHIFT >

SUMMARY
Shift the spectrum up or down by adding a value (positive or negative) to all specified frequencies. The whole spectrum may be shifted (Mode 1), or you can shift above or below a given point (the "divide frequency": Modes 2 & 3), or shift only within or outside a given frequency band (Modes 4 & 5).

MODES

 1. Shift whole spectrum: Raise/lower all partials by shift frequency.
 2. Shift above divide freq.: Raise/lower partials above dividing frequency freq split.
 3. Shift below divide freq.: Raise/lower partials below dividing frequency freq split.
 4. Shift inside freq. range: Raise/lower partials inside range low freq to high freq.
 5. Shift outside freq. range: Raise/lower partials outside range low freq to high freq.

OPTION
Interpolate logarithmically between frequency values when time-varying (default: linear).

PARAMETERS
 shift freq  Shift value added to all partials within specified range (see Modes).
A positive value compresses the intervals between partials, negative stretches them (+/-22050 Hz)
Range: -22050 to +22050 Hz, but note that partials shifted below 10Hz (?) or above 22050 Hz will be lost. T-V
 freq split (divide-frequency): shift above (MOde 2) or below (Mode 3) this point.
Range: 10.77-22039.23 Hz for 512 chans. T-V
 low freq Bottom frequency of range to shift within (Mode 4) or outside (Mode 5)
Range:  10.77-22039.23 Hz for 512 chans. T-V
 high freq Top frequency of range to shift within (Mode 4) or outside (Mode 5)
Range: 10.77-22039.23 Hz for 512 chans. T-V
 
NOTES
Spectral shifting raises or lowers frequencies, but also alters the musical intervals between partials. Harmonic sounds in particular become inharmonic ("bell-like"). Shifting upwards narrows the ratios between partials, while shifting down widens them. Partials which are shifted outside the total frequency range are lost. As all parameters are time-varying, there is great scope here for evolving timbral change.

In the analogue frequency shifter, an extreme lowering of partials causes negative values (below 0 Hz) to be wrapped around to positive values 180° out of phase. This is not possible with SHIFT or most digital shifters; however, it might be possible to simulate the effect with a combination of processes (including FILTER, SHIFT, INVERTSPEC).


© Ensemble Software and Composers Desktop Project 2014