12/8 is compound yet it treats it as simple

• Oct 3, 2018 - 04:37

12/8 is the time signature I am writing my nocturne in. If I were writing with pencil and paper I wouldn't have to deal with this but I have basically 2 options here as far as the time signature and notation and 1 of them is technically correct but is time consuming and the other is wrong for the right hand.

Technically correct but time consuming option:
I could write it in 4/4 in the notation software and make each group of eighth notes a triplet and notated as such, then select all but 1 triplet and make it invisible and then type in sempre for the left hand.

Wrong but easier option:
I could write it in 12/8 and put in dotted quarters where I have 1 note in the right hand for every group of 3 in the left hand. But this looks wrong to me. After all a dotted quarter in 12/8 is really 4.5 eighth notes, not 3.

This would be way easier if musescore like automatically did it in compound meter for time signatures with 6 or more beats(5/4 I have seen represented as simple quintuple meter instead of 2/4 + 3/4 or vice versa) so it would have 4 quarter notes instead of 6 in 12/8.


After all a dotted quarter in 12/8 is really 4.5 eighth notes, not 3.

Well, no. In any given time signature, compound or simple, a dotted quarter will always be worth 3 eight notes. A time signature of 12/8 means that there are 12 beats in a measure, and the eighth note gets a beat. Thus there are 6 quarter notes, or 4 dotted quarter notes, in a 12/8 measure.

Now, suppose you were to write the right hand in 4/4, and the left hand in 12/8. (You can do this in MuseScore by making use of local time signatures). Then you could have a quarter note in the right hand for every 3 eighth notes in the left. (And a dotted quarter in the right hand really would be worth 4.5 eighth notes in the left, like you said.)

To be absolutely clear: MuseScore is treating 12/8 correctly. A dotted quarter is equivalent to three eighths regardless of the time signature. In 12/8 or any compound meter, dotted quarters represent the basic pulse, and eighths will be beamed in groups of threes to correspond with this. Check any reference on published score in 12/8 and you will see this.

In reply to by Marc Sabatella

But I see lots of pieces written in 12/8 or 9/8 where the composer wrote a quarter note and expects you to play that quarter note over 3 eighth notes, in other words they are basically writing implied triplets and writing the right hand as though it were in 4/4 or 3/4 but still writing the time signature for the right hand as 12/8 or 9/8. I see this especially with Chopin.

In reply to by Caters

Here is the first line of a nocturne in 12/8 written by Chopin:
You can see that the dotted quarters are equivalent to three eighth notes, and quarter notes are equivalent to two eighth notes.
Now, here is a line from Op. 55 No. 1, which is written in common time:
The eighth notes are obviously triplets, even though they are not marked as such. To notate this in MuseScore, they would have to be entered as triplets. Then you could right-click one of the tuplet numerals, choose "Select->All Similar Elements", and uncheck "Visible" in the Inspector (or press "v").

In reply to by Caters

I won't say no professional editor has ever chosen to use such a non-standard notation, but if it has happened, it is most definitely rare and quite incorrect. If they choose to write in 12/8, they should be using dotted quarters for the beat like everyone else does.

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