Improper tuplet beaming

• Sep 23, 2016 - 16:15
Reported version
Graphical (UI)
S4 - Minor

Quaver triplets in 3/8 time join a beam incorrectly to a subsequent quaver. bad triplet beaming.png


Thanks for reporting

See also Affects lastest build from master too.

(The assigned field is meant for the developer working the issue, and this issue is far from major)

The odd measures show the (wrong) default beaming, the even measures show what they should look (and do after manual intervention using the beams palette)

Title Bad triplet beaming Improper tuplet beaming

The issue appears to be independent of the number of notes in the tuplet group, of the duration of the preceeding or following notes, and of the time signature, as well.

bad tuplet beaming 2.png

In the above example in 3:8 time, triplets, quintuplets, and sextuplets in both 16ths and 32nds beam improperly with 8ths and 16ths.

bad tuplet beaming 3.png

In the second example, in 4:4 and in 5:4, triplets and quintuplets beam improperly with 8ths and 16ths.

My thought would be to create a rule which beams all tuplet groups independently of what preceeds or follows them, as default behaviour. If the user wishes to modify that beaming for whatever reason of his own, it should be possible to do so using either the Beams and Spacers palette, or the Time Signature Properties dialogue.

Jojo, is this a practical approach?

That's not a correct rule - sixteenth triplets can be beamed to eighths. Which is to say, your measure 10 is correct as is. The rule needs to be something more like, don't beam a triplet to a note of the same rhythmic value as the fundamental division of the triplet.

For the record, our actual rule is to consider notes in a tuplet as if they were the next shorter duration. So in an eighth note triplet, the notes are considered as if they were sixteenths, and beamed accordingly. In 4/4, this works as expected - a triplet of three eighths makes up a full beat and will be considered as if they were sixteenths, and as such not be beamerd to other eighths in other beats. But this heuristic fails in compound meter, where a triplet of three eighths doesn't take a full beat, so conisdering them as sixteenths fools us into thinking it's OK to beam them to the third eighth of the beat.