How many measures minimum in a repeat

Question

I know that a "repeated section" (i.e. I'm explicitly thinking about "enclosed in repeat-barlines") may be however long, 1 measure or 100. However, I'm wondering, whether there are "good" rule-of-thumb-like rules about when to use repeat signs in non-experimental pieces.

I came across a music sheet, where the first measures are like this:

ABCDBCE

And I'm wondering, whether it is OK to write it with a repeat on the measures BC with two different endings, something like:

A"BC"1D2E

Any pointers are welcome.

Answer 1

...measures BC with two different endings...

Are the alternate "endings" in your example actual endings? If not, using voltas and repeats would seem to send the wrong visual clues about what is happening musically.

In other words, internal repetition within a phrase and alternate endings are not the same.

Regarding a rule of thumb, it seems to me the important thing is distinguish formal types of repetition. I can think of three types (I'm naming categories on the fly here:)

Mechanical...

...pretty obvious in the case of exercises, but could also be sensible for something like an ostinato part. Repeat signs visually reinforce the idea to just keep doing something over and over. Perhaps when the exact number of repeats is lost upon the listener.

Proportional...

...or...

...the two-bar ideas could be enclosed in repeats, but they are written out. Often in classical music such repeats have some small variation necessitating the second iteration be written out, but even when it's a literal repeat it's still written out.

I call this "proportional" because I think the purpose of the repeat is to simply extend 2 bars to fill the space of 4. In both examples the sonatas both have phrase groups based on 4 bars. Composers could achieve 4 bars a number of ways in terms of repetition: 4 unique bar, a repetition with variation, or a literal repetition. If all three are consider just the same thing - a 4 bar phrase - then we can see why repeat signs aren't normally used for the literal repeat. It isn't so much that musical idea is about repetition, but filling the space of the proportions.

I think the listener is normally very aware of the repetitions, usually 2, maybe 3.

Structural...

...it's hard to show with a short example, but these are the repeats demarking the first and second halves of a sonata. Of course sectional repeats like this simply double the play time. But, especially in the case of sonata form, the repeats emphasize the structural significance of the sections. You could abbreviate it like ||: I V :||: ? I :|| where ? means the "development" part. The repeated sections help emphasize that the first part sets up an incomplete ending (ends on the dominant) which is then made whole by the second part ending on the tonic. Repeats like this make the structural organization clear. In the case of classical form, it's tonal/harmonic contrasts demarked by sections and their repetition, but I suppose structure/repeats could be based on other aspects rhythms or melody.

I think for a casual/untrained listener these repeats may not be apparent regardless whether there is a clear stop at the end of sections.

Answer 2

With music notation, one important consideration is legibility; and on that count I’d suggest that your single-bar example fails the test, in that it introduces navigational complexity without saving much space on the page.

There may well be musicologists who have devoted treatises to the subject, but I suspect a good ‘rule of thumb’ would be ‘does this repeat make the music easier or harder to read’?

Answer 3

Typically repetition is used for a whole section, a closed piece of music, like a verse of a song, a part of a dance. I don't believe there are strict rules there. Perhaps you may ask yourself: would the score make logical sense if you put a double bar line at the boundaries of the repetition? In practice I rarely see repeated sections shorter than 8 bars.

If you're desperately looking to shorten the length of the score, e.g. to fit it on one page, then anything is permitted, but you are likely sacrificing readability, especially with something as short as two measures with voltas. I wouldn't recommend doing it on a regular basis.

Answer 4

I suspect it depends on whether the musician playing it primarily sight reads or plays by ear.

I finally stopped flunking site-reading tests when I learned to sight sing, so that I could just ignore the printed music and concentrate on playing what I'd just sung. I eventually got better at sight reading, but I like short marked repetitions as they allow me to read once and then play twice.

In contrast, my mum could sight-read music as a child before she learned to read English, so for her using repeats on short blocks is pointless, and having to relocate her visual focus on a repeat block is somewhat of a distraction.

That said, repeats that go back to previous pages are worse distractions, and short be avoided if possible.