A group of notes with feathered, or fanned beams “indicates free accelerando or rallentando within the duration” of the group, according to Elaine Gould in her music notation reference Behind Bars (which, in case you missed our last post, is now available in digital format). The convergence of the beams indicates the slowest point of the group; the fully-feathered beams indicate the fastest point:
The notes may be spaced evenly:
Or — my preference — the notes may be spaced according to their speed:
Since this feature was introduced in Sibelius 6, it’s been quite straightforward to create groups like those in the former example, so we’ll start there.
Simply enter the notes as ordinary 32nd notes:
Then, select the first note of the beamed group (or sub-group), switch to the third Keypad layout, and click the appropriate beam for either accelerando or rallentando (shortcut 0 and . respectively):
The result is this:
It’s important that all of the notes of the beam are the same duration for Sibelius to display a feathered beam. You’re not obligated to cram eight 32nd notes into the space of one quarter note if the music doesn’t demand it; you can create the notes as tuplets in your desired ratio (Note Input > Triplets > Other). Join the beams by selecting the appropriate notes and click the Middle of beam option in the third Keypad layout.
Then hide the tuplets by selecting them and hiding them — either by going to Home > Hide or Show or opening the Home > Inspector and under Tuplet: choosing None for the ratio and No bracket for the bracket style.
Spacing according to speed
We can use this approach to create feathered beams that are spaced according to speed, as in the second Gould example. Create tuplets in progressively increasing or decreasing ratios, depending on whether you’re creating an accelerando or rallentando (despite their nested appearance, the tuplets aren’t nested — it appears to be a bug which we can ignore for now):
This is essentially two 32nd notes in the space of eight 32nds, followed by three 32nd notes in the space of 32nds, etc.
Now, make the feathered beam by clicking the appropriate icon in the Keypad:
And then hide the tuplets. Here’s the result, with a comparison against straight eighth notes for reference:
Here’s a more real-world example:
Naturally, the playback and display of notes in the feathered beams will be an approximation compared to how a live player would perform them; otherwise, you’d actually write strict tuplets! But by following this method and spacing the notes according to their speed, you’ll have a more realistic representation of these types of passages, especially in context with other instruments playing measured notes.