Take a X/4, it means "the measure will contain X notes, the value of which are 1/4"

I understand this concept for X/Y signatures, with Y being a power of 2. But what does that mean for the others ?

For instance, what would be a 3/9 time signature ? A measure that contains 3 1/9th notes ? But what's a 1/9th note ?

  • Three groups of what type of notes constitute 3/9 time?
    – Neil Meyer
    Commented Aug 29, 2015 at 16:25
  • 3/8 is three 8th notes, so yes, theoretically 3/9 is 3 ninth notes (one-ninth of a whole note). I do not believe there is a generally accepted notation for 1/9 notes. Furthermore, 3/8 would be a much easier alternative.
    – michaeljan
    Commented Aug 30, 2015 at 0:53

3 Answers 3


While the typical notes are based on divisions of 2 (i.e. whole, half, quarter, 8th, 16th, ect) using tuples you can have almost any ratio of notes you can utilize to split up a measure.

Here is a layout of notes evenly splitting up a measure of 4/4 from whole notes to what you could call 9ths:

enter image description here

As you can see all take up a whole measure of 4/4 and divided them equally and you could theoretically give any one of the notes below the beat which is what the denominator is for.

In practice however, this is not really very useful as not only notating something like 3/9 difficult due it's tuple nature, but in reality you would be much more inclined to view it as 3/8 because the only difference you would feel is a slightly faster tempo which is much easier to notate then part of a sequence of tuples across a measure.

The version of Finale I have won't even let me mock up a measure of 3/9 for you for that reason, but it can be achieved and I'll eventually show it on manuscript.

  • That gives no indication of time signature. Just because a bar has nine notes does not make it nine time. You seem to have a warped idea of what time signatures are
    – Neil Meyer
    Commented Aug 29, 2015 at 16:36
  • @NeilMeyer it's all 4/4 demonstrate how you can achieve other notes that could be used as a base of other time signatures. I can send you the finale file or export it to mp3 if you want to hear it and see it.
    – Dom
    Commented Aug 29, 2015 at 16:36
  • 1
    There are some examples with playback here, and a link discussing how to fake the notation in Finale: midnightmusic.net/MusicTheory/advanced/UnusualTimeSigs.html
    – user19146
    Commented Aug 29, 2015 at 17:21
  • Note that I took 3/9 just as an example :), I wouldn't seriously think about using it, I was just being curious.
    – user23227
    Commented Aug 29, 2015 at 18:39
  • Having slept on it, I'm attempting to understand what Neil's stumbling block is. I think it's the term 'time signature'. In all your examples, the bottom number is 4. In the 'time sig'. All that's happened is the number of notes still fit into one bar - 4 'beats' long, in time. In fact, with each successive bar speeded up a little, you could have written 4/4, 5/4, 6/4, 7/4 etc, as they all contain the '4' part - crotchets. There surely isn't a dot that signifies, say, 1/9th of a semibreve. There's no need. One unit can be written as a crotchet, quaver, etc. Then you can use 9 in one bar?
    – Tim
    Commented Aug 30, 2015 at 5:57

Take a simpler example: what would a time signature of 2/3 mean?

If you divide a whole note into three equal parts, in conventional notation you would write that as a triplet of half-notes (= UK minims). But suppose you want the music contain some normal-length half-notes followed by just two notes at the speed of a triplet, and them continue normal-length notes.

You could mark one bar to be played at a faster tempo (MM mark) and then revert to the original tempo, but the performer would then have to "do the math" to figure out what was intended. If the tempo marks were MM 76 and 114 it's not obvious to most people that the ratio is exactly 3:2.

You could write a series of triplets with notes tied from one to the next, but that would be unreadable except for a short passage of music.

The new notation of a 2/3 time signature was invented as a neater way to write this. It's easier to "read" the exact relation between time signatures like 2/3 and 2/4 than between MM marks of say 76 and 114.

Some composers have used a different notation, where the denominator remains a power of two (showing the length of the beats) but the numerator is itself a fraction - for example (5/3)/4 would be a bar length of a quarter-note plus two-thirds of a triplet of 8th-notes. Of course you could write that more conventionally as 3+2+2/8 or 7/8, but hey, avant garde music needs to look cool, and 7/8 is way too old school for that.


The denominator doesn't have to be a power of 2. From Wikipedia:

  • The lower numeral indicates the note value that represents one beat (the beat unit).
  • The upper numeral indicates how many such beats there are grouped together in a bar.

For instance, 2/4 means two quarter-note (crotchet) beats per bar and 3/8 means three eighth-note (quaver) beats per bar.

So 3/9 means 3 ninth-note beats per bar.

  • But what's a ninth-note ? How do you represent it for instance ?
    – user23227
    Commented Aug 29, 2015 at 12:21
  • 1
    It is a ninth as long as a whole note. Just divide by nine
    – Doktor Mayhem
    Commented Aug 29, 2015 at 12:28
  • 1
    there is no such things as a ninth note it is total rubbish.
    – Neil Meyer
    Commented Aug 29, 2015 at 14:33
  • 1
    Neil - I'm afraid you are wrong. You can have any number there. It's very straightforward.
    – Doktor Mayhem
    Commented Aug 29, 2015 at 14:50
  • 1
    @NeilMeyer you can see my answer.
    – Dom
    Commented Aug 29, 2015 at 16:32

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