Currently Dorico sets the limit for fanned beams up to 32nds (this follows the examples shown in Gould, p.158) however the literature contains several examples where fanned beams go beyond this limit. (For instance in pieces that go up to 64ths and 128ths if one needs a fanned beam to display accel. or rit. It wouldn’t be coherent for the latter to be limited to 32nds).
The example below is from Crumb’s black angels which displays a fanned beam of 64ths in the 1st violin, the 64ths in the 2nd violin below explains this choice.
if you are bringing some additions to the fanned beams, I would love to have some kind of a system that positions the notes automatically accelerating/rallentando. Tweaking them every time is irritating (adding imaginary smaller values, moving them in the Note Spacing). Also, a playback would be amazing!
Just a spontaneous idea/dream/fantasy: The first note is 64nth, it is followed by eight notes (let’s say 32th) and one 16th note. You click “Create Fanned Beam”. Out comes a fan that begins as 64th (four beams) and ends as a 16th (two beams), it has altogether ten notes, the first and last one have their original durations, notes between have durations that go linearly from one to another (these values would probably get rather groovy, so they will need to be simplified, of course). The duration of the whole fan would be the duration of the original notes. These note values are then used for positing the notes and more importantly for playback.
I wouldn’t use them in any naughty ways, promise!
Also, a pony.