Staff Rules : Advanced features

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Staff Rules
Advanced features

We saw rules enable to make several instruments play on the same staff, by differenciating notes according to graphical criteria.
But this system enables to go further.

Special parameters

The "Special" button in staff rule editing window lets you set parameters (effects, velocity, delay...) that will be applied to the note when played.
Example of use :
An interesting application is to use configurable "Turkish comma" effects to define an alternate tuning. Alternate tuning is useful for playing non-occidental melodies, or pieces that complies to frequency rules other that the 12 semi-tones equally tempered (12ET) "usual" scale. Microtonal adjustment and Alternate tuning chapters will provide more information about these topics.

Non-blocking rules

Previously, we learnt notes that comply to a rule criterion (color, pitch, shape...) are played in a particular way.
As soon as a note match a rule, instrument and/or special parameters of the rule are applied to the note, but the remaining part of the rule set is then skipped.
For example, if you build a rule based on blue color, that changes the instrument in "Organ", then another rule based on triangular note head shape, that changes the instrument in "Guitar", then a blue note with triangular head will be played using the "Organ" sound, first rule to match the note characteristics.

It is now possible (grom Harmony Assistant 8.0, Melody Assistant 6.0) to define non-blocking rules. If the "Continue processing" box is checked, rule search does not stop as soon as this rule matches. Thus, the previous note will be played both on "Organ" and "Guitar" instruments.

Example of use :
It is possible, by using this feature, to define staves on which several simultaneous instruments play the same notes.
You can also define an instrument related to shape (for example, cross-headed notes play on "Slap bass") and another one related to color (for example, red notes are played with a "bend" effect). Thus, red cross-headed notes will be played using "slap bass" instrument and with a bend effect.

"Fundamental note" marker

If the box "note is the fundamental" is checked in a rule definition, notes that match this rule will be considered as the chord fundamental note (root note). This chord fundamental enables other rules (even located on a different staff) to be applied according to the relative position of the note pitch in the current chord. You can define this way rules that apply only to thirds or fifths of the current chord (see below).

Note pitch rule criterion

This rule criterion enables to apply the rule only to notes of a given pitch. Some check boxes can change the way the note pitch criterion is evaluated :

If nothing is checked, pitch is evaluated in an absolute way. For example, if you set the pitch criterion to the note on the botommost staff line, with a flat accidental, only E flat, 4th octave notes will match this rule, as well as D sharp, 4th octave notes.
If you check "For all octave" box, any E flat or D sharp (whatever their octave is) will match this rule.
If you check "Follow key signature" box, note pitch criterion is relative to the base note of the current key signature. Your rule will therefore match E flat and D sharp when key signature is major C, but for example, B flat or A sharp if the key signature is major G.
If you check "Differentiate enharmonics" box, E flat and D sharp won't be considered anymore as the same note. Only E flat notes will match this rule
If you check "Relative to fundamental" box, note pitch criterion is considered as relative to the chord fundamental that has been defined through another rule (see above). C pitch means "Equal to the fundamental", C sharp means "equal to the fundamental plus one semitone", etc. For examplen to apply a rule to major third of the current chord, you must enter "E" as note pitch rule criterion.

Examples of use :
- By building a rule like : "notes with a triangular head are the fundamental note of the current chord", you just have to mark all notes that are root of their chord to make other rules apply to, let's say, major thirds or fifths of any chord of your score. Only by selecting an appropriate name to your rules, you can then add a "3" mark to all thirds, "5" to all fifths, in order to display the chord-relative name for each note.

- By combining the alternate tuning and chord fundamental relative pitch criterion, it is possible to alter chort component (third, fifth, minor seventh) frequencies (tierces, quintes, septièmes mineures) so that they are played "just", i.e. at an exact sub-multiple of the chord fundamental note frequency. This can for example be used in "Barbershop" choirs, in which singers adjust their voice pitch according to the fundamental, in order to minimize phasing effects that are due to the imperfection of the traditional occidental scale tuning.

"Velocity" criterion

This criterion enables to define rules that apply to notes according to their velocity. You can, for example, not use the same instrument for notes that are played softly, and for those played loud.
Because note velocity is not easily visible on score, this kind of rule must be used carefully.
This criterion is applied or a given range of note velocity, and enable to define the velocity range that is played instead.

Examples of use :
- Build a rule that applies on velocities from 0 to 64, and that outputs on "Organ 1" instrument, with an output velocity range from 0 to 64 too (velocity remains unchanged)
Then, build a rule that applies on velocities from 65 to 127, and that outputs on "Organ 2" instrument, with an output velocity range from 65 to 127 too (velocity remains unchanged)
Soft notes will be played on "Organ1", loud notes on "Organ 2"

- By combining with the "Continue processing" option (non-blocking rule) it becomes possible to mix smoothly two instruments according to the original note velocity on staff.
To do this, build a rule that applies on velocities from 0 to 127 (whole available range) and that outputs on "Organ 1" instrument, with an output velocity range from 127 to 0 (velocity is inverted : soft notes will be played loud on this instrument, and loud notes will be played soft)
Then , build a rule that applies on velocities from 0 to 127, and that outputs on "Organ 2" instrument, with an output velocity range from 0 to 127 (velocity remains unchanged)
Soft notes will be played on "Organ 1" instrument, loud notes on "Organ 2", and intermediate values will be played on both of them, the influence of "Organ 2" becoming bigger as note power increases.

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