blocked-keys

blocked-keys silences a fixed set of keys; everything else passes untouched.

This is the silent hand of Ligeti’s Touches bloquees: keys held down so the playing hand’s strikes on them produce nothing but the gap. Run a fast even line across a blocked patch of keyboard and the holes turn it into jagged, syncopated rhythm you never played. The blocked notes are not remapped, they are simply absent.

A blocked note-on is dropped and its matching note-off drops with it, so nothing is ever left hanging.

Parameters

blocked-keys takes the keys as bare arguments, at least one.

Parameter	Type	Default	Range
keys	integer arguments	required	0..=127; pitch classes 0..=11 with by-class=true
by-class	boolean	false	true, false

With by-class=true the arguments are pitch classes, blocked in every octave: blocked-keys 0 by-class=true silences every C on the keyboard.

Example

miditool.kdl

input "Roland"
output virtual="miditool Out"

blocked-keys 60 62 64 65 67      // a hole in the middle of the keyboard

Try this

Block all five black-key pitch classes, in every octave:

blocked-keys 1 3 6 8 10 by-class=true

Now hammer chromatic runs and glissandi; only the white keys survive, and the missing notes are the groove. Then flip it, blocked-keys 0 2 4 5 7 9 11 by-class=true, and you are playing the pentatonic ghost of the same gesture.