Stromian Tuplet Notation

Nested nested triplet

Nested tuplet from polyriddim by phonon

Nested tuplet used frequently in The Black Page by Frank Zappa

Stromian tuplet notation is a system for expressing tuplets. The main purpose of STN is to convey complicated tuplet ideas over text. The system strikes a balance between legibility and efficiency.

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The notation system used on the Metr tool on chambercode.com is very similar to STN, the main difference being that it doesn’t have STN’s redundant numerator.

Stromian vs. Metr notation

	Tuplet	Notation
Stromian	11:8 with a nested 8:6 at the beginning	11[8:6+5]:8
Metr	11:8 with a nested 8:6 at the beginning	[8:6+5]:8

Limitations

Ambiguity

When written with STN, the exact length of the tuplet can be ambiguous. If there’s a 4 in the denominator, that could mean that the tuplet is 4 quarter notes long, but it could also be 4 eighth notes, 4 sixteenth notes, etc. This ambiguity can be solved by writing the denominator as a time signature instead of a plain number.

11[8:6+5]:8 —> 11[8:6+5]:8/8

Legibility

A triplet inside of a nested triplet is pretty easy to conceptualize when reading it on sheet music, as opposed to STN, where it would be written like “3[3[3:2+1]:2+1]:2”. STN has its limitations, but it allows those familiar with it to glance at “11[6+9:5]:8” and think “ah yes, a 11:8 tuplet with a nested 9:5 at the end”.