A description of how to encode tremolos in **kern spines.

Tremolos are represented in **kern by encoding the individual notes in the tremolo within a single beam group, and then adding a *tremolo tandem interpretation before the beamed notes that should be converted into a tremolo.

Use *Xtremolo to turn off tremolo conversion of beamed notes:

When *tremolo is active, only beamed groups that can convert into tremolos will be converted into tremolos. Other patterns of beamed notes will remain unaffected.

Tremolos also work with beamed chord notes

Fingered tremolos

The *tremolo interpretation can also reduce alternating notes into tremolos:

Two-note tremolos also work with chords:

Unmeasured tremolos

Unmeasured tremolos are not expected to be played exactly as written, and function more as ornaments. Thirty-second note tremolos are often unmeasured tremolos, and can be encoded in the following alternate way.

The number of tremolo lines is indicated by the repetition of the letter O in the token.

The line:

!!!RDF**kern: O = tremolo

defines the O character in **kern data to represent a tremolo. O is the upper case letter o which means a generic ornament in **kern data. Other user signifiers could be used as well, but using O is useful if you want to categorize the tremolo as an ornament like a trill.

Disabling tremolos

Tremolos can be disabled from notation rendering by using the shed filter. Add the following line to a file to temporarily disable tremolos:

!!!filter: shed -e 's/^X?tremolo$//I'

This filter changes both *tremolo and *Xtremolo interpretations to the null interpretation, *.

To preserve the tremolo interpretations within the data for later reconstruction of tremolos, use instead something like:

!!!filter: shed -e 's/^(X?tremolo)$/$1-disabled/I'

Here is the compiled output of this filter:

To restore the tremolos again, use this filter:

!!!filter: shed -e 's/^(X?tremolo)-disabled$/$1/I'

Tremolo filter

The tremolo filter can be used to add tremolo notes to a Humdrum score that does not have expanded tremolos. To expand a single note into a tremolo, add the duration of the tremolo surrounded by @ markers after the note token(s):

Scores should not be stored in compressed tremolo format, as the @ encoding is only intended to add tremolos to the score using the tremolo filter. Here is the result of compiling the filter:

Two-note tremolos are encoded in a similar manner. Place the duration for the tremolo only on the first note of a two-note pair, surrounded with two @@ characters rather than one. Each note of the pair should posses one-half of the total duration of the tremolo.

The result of compiling the filter: