CDP Sound Examples – SPECTRAL TUNING

Tuning a sound's spectrum to a user-defined chord

SOURCE SOUND

horn.mp3 (French Horn, ca. C# above Middle C)

TRANSFORMATION

extun1.mp3

DESCRIPTION
~ CDP Function: PITCH TUNE ~

• This tuning function operates in the Spectral Domain. Its input is therefore an analysis file.



• You can define the chord either in frequencies (Hz) or as MIDI Pitch Values. Note that the CDP documentation includes a chart of 'Equivalent Pitch Notations' to help do this.



• The tuning happens within the spectrum of the sound. The sound is not duplicated at different pitches (a mixing operation), but the frequencies, the partials within the spectrum, are moved where possible and highlighted to match the pitches defined by the user. Non-template partials are then discarded.



• I think it is true to say that this tuning is enhanced if the tuning pitches are within that part of the spectrum which has the most energy (loudest partials). The spectral information function PEAK locates the time-varying energy centre of the spectrum.



• Experience has shown that Richard Dobson was right to advise that fairly widely spaced pitches, as in 'open chord' formations produce a better result. When the tuning pitches are close together, a good part of the original sound is 'let through' and the clarity of the tuning is less effective.

Additional Information

PARAMETER SETTINGS
(Click on image to view fullsize)

KEY POINTS

• As with many CDP functions, you have options which affect the degree to which the original sound is retained. In this case, the 0 values allow the maximum amount of



• In this case, the 0 values allow the maximum amount of original sound to remain, and the 1 values emphasise the tuning rather than the original sound. Inbetween values allow you to find the right balance point for your musical context, and the parameters can be time-varying (automated changes).



• Thus focus is like Q: the degree to which the function narrows to the defined pitches.



• Clarity relates to how much the non-template partials are suppressed.



• And trace, like the function HILITE TRACE, controls the number of spectral components to retain in each analysis window.



• Finally, basscut enables you to specify at which frequency to begin tuning: above is tuned, below is left as it is.

SUPPLEMENTARY FILES USED

User-Defined Tuning Pitches (Given as MIDI Pitch Values)

[miditata.tun]
48 55 58 62 69 76

These pitches are, in ascending order, Low C (48), Low G (55), Bb below Middle C (58), D above Middle C (62), A above Middle C (69), and E above High C (76):