shuffle-lock

shuffle-lock permutes the keyboard: every key plays some other key, and the mapping never changes.

Press C4 and get, say, F#5, every single time. The keyboard becomes a strange but stable instrument. Melodies you know come out as lines you would never write, voice leading turns into leaps, and yet the whole thing rewards practice, because the scramble is locked to its seed. Same seed, same scramble, forever; see Seeds.

Note-offs follow the same mapping as their note-ons, so held and overlapping notes always release correctly.

Parameters

Parameter	Type	Default	Range
seed	integer	required	any unsigned 64-bit value
lo	key number	21 (A0)	0..=127, at most hi
hi	key number	108 (C8)	0..=127
mode	string	"free"	"free", "within-octave", "within-pitch-class"

Only keys in lo..=hi are permuted; the defaults cover the 88 keys of a piano. Keys outside the range pass through unchanged.

mode constrains the permutation:

• "free": any key may land anywhere in the range.
• "within-octave": keys stay in their octave. Registers keep their character; lines stay in place but the intervals scramble.
• "within-pitch-class": keys keep their pitch class and move between octaves. Harmony survives; every C is still a C, just not the one you pressed. Chords splay across the keyboard.

Example

miditool.kdl

input "Roland"
output virtual="miditool Out"

shuffle-lock seed=42 lo=21 hi=108 mode="free"
velocity-curve gamma=0.8

Try this

Keep the harmony and scramble only the registers:

shuffle-lock seed=42 mode="within-pitch-class"

Play a chorale. The voices explode across seven octaves but the progression is untouched. Then reroll the seed live until the spacing sits well.