Adaptive just intonation: Difference between revisions

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'''Adaptive Just Intonation''' (or short '''Adaptive JI''') is an approach to tuning that employs predefined musical intervals as frequency ratios over a floating tonal center that is defined by the most recent context.
'''Adaptive just intonation''' ('''adaptive JI''') is an approach to [[just intonation]] that employs predefined musical intervals as frequency ratios over a floating tonal center that is defined by the most recent context.


== Description ==
== Description ==
In an adaptive JI context, any given moment during a piece of music has a reference pitch to which the rest of the music is compared.   
In an adaptive JI context, any given moment during a piece of music has a reference pitch to which the rest of the music is compared.   


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Then the D in the IV chord is 4:3 with respect to A, which was the tonic of the chord immediately proceeding it.  The E in the E7 chord is the same whether defined relative to the proceeding D chord (9:8 relative to D) or referencing back to the original tonal center of A (because 3:2 is the same as 9:8 of 4:3), but the D in the E7 chord is 9:5 relative to the E (9:5 of 3:2 is 27:20 compared to the original A), which is different than the D in the proceeding D major chord (which was 4:3 compared to the original A).
Then the D in the IV chord is 4:3 with respect to A, which was the tonic of the chord immediately proceeding it.  The E in the E7 chord is the same whether defined relative to the proceeding D chord (9:8 relative to D) or referencing back to the original tonal center of A (because 3:2 is the same as 9:8 of 4:3), but the D in the E7 chord is 9:5 relative to the E (9:5 of 3:2 is 27:20 compared to the original A), which is different than the D in the proceeding D major chord (which was 4:3 compared to the original A).


==Software==
== Software ==
 
* [http://www.math.tu-dresden.de/%7Emutabor/ Mutabor] Windows, Linux and Mac OS X. Uses its own programming language to describe pitches, (re)tunings and reactions to events.
* [http://www.math.tu-dresden.de/%7Emutabor/ Mutabor] Windows, Linux and Mac OS X. Uses its own programming language to describe pitches, (re)tunings and reactions to events.
* [http://www.TallKite.com/alt-tuner.html alt-tuner] PCs, macs and Linux/Wine. DAW plug-in (requires [http://reaper.fm/ REAPER]) that retunes almost every midi keyboard or softsynth.
* [http://www.TallKite.com/alt-tuner.html alt-tuner] PCs, macs and Linux/Wine. DAW plug-in (requires [http://reaper.fm/ REAPER]) that retunes almost every midi keyboard or softsynth.
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* [https://www.dmitrivolkov.com/projects/pivotuner/ Pivotuner] VST3/AU plugin for macOS/Windows. Uses fixed just intervals to a dynamically-changing root.
* [https://www.dmitrivolkov.com/projects/pivotuner/ Pivotuner] VST3/AU plugin for macOS/Windows. Uses fixed just intervals to a dynamically-changing root.


==Compositions==
== Music ==
 
* [http://eceserv0.ece.wisc.edu/%7Esethares/mp3s/localanomaly.html Local Anomaly] by William Sethares
* [http://eceserv0.ece.wisc.edu/%7Esethares/mp3s/localanomaly.html Local Anomaly] by William Sethares
* [http://eceserv0.ece.wisc.edu/%7Esethares/mp3s/three_ears.html Three Ears] by William Sethares
* [http://eceserv0.ece.wisc.edu/%7Esethares/mp3s/three_ears.html Three Ears] by William Sethares
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== External links ==
== External links ==
* [http://www.tonalsoft.com/enc/a/adaptive-ji.aspx Definition of Adaptive JI (Tonalsoft encyclopedia)]
* [http://www.tonalsoft.com/enc/a/adaptive-ji.aspx Definition of Adaptive JI (Tonalsoft encyclopedia)]


[[Category:Just intonation]]
[[Category:Just intonation]]