Beaming in different time signatures

I'm studying music theory in the UK, aiming for ABRSM Grade 5, currently working for grade 3. I'm having trouble grasping the rules for when to beam quavers.

In my study book, by Eric Taylor, I see these "rules".

1. Beam together four quavers which could be replaced by a minim. Example: in 3/4 4 beamed quavers, followed by a crotchet.
2. In 4/4 beam together 4 semi-quavers, so a bar of sixteen semi-quavers, we have 4 beamed groups of four, one group per beat.
3. In 6/8 we beam in two groups of three, one per group per beat.

So here we seem to have two different approachs. In the 4/4 and 6/8 cases we beam "per-beat", in the 3/4 case we beam across two beats. So the 3/4 case seems to be anomalous.

Is there a simple rule here, or maybe a general rule with 3/4 as an exception?

-

Disclaimer: I've never studied for ABRSM or similar exams; only did some amount of theory in school.

I think (what I was taught anyway) it is mostly aesthetics. In 4/4 it is also common to beam 4 quavers over two beats, when the four falls in one "half" of the measure. The general idea of beaming is to make your notation more readable, and adhering to "natural" division boundaries in the measure (such as beat boundaries, or groups of beats).

(Also, I'd have thought that there are 6 beats in a 6/8 time signature by definition, even though it is a compound signature...)

-
Thanks. I must admit I'm puzzled by the 6/8 rule, but that's how the book describes it. – djna Apr 27 '11 at 9:33
6/8 is confusing as heck. It IS theoretically possible for it to be meant as six beats, but I've never, ever seen it; literally almost all of the time, 6/8 is two compound beats. Look into Orff Time Signatures for an interesting perspective on this. – andyvn22 Apr 28 '11 at 0:50

Here is an opinion from a designer: When you beam notes, you create gestalt groups and the beamed notes are perceived to be together. Beam your notes in a way that makes sense in the context of the music that they be perceived as a single group of beats.

In other words, let your notes conform to your music, not the other way around.

-
-1: Notes should be beamed based on metric properties, not based on musical ideas. Large-scale slur markings can convey that, but beaming based on musical motive is very nonstandard and would be extremely confusing to most performers. – andyvn22 Apr 28 '11 at 0:47
I actually agree with everything in this answer, so long as it is not unreasonably extended to the degree that @andyvn22 suggests might be the case. If the time signature you're working in is "correct" for the music you aim to write, you will generally be okay beaming in the manner that conveys your musical subdivision of that meter. For example, 8/8 time can be 3+3+2, 2+3+3, etc, and the beaming would convey that subdivision. The beaming suggested by the asker in 3/4 time would convey a fast 3 with a waltz subdivision of 2+1. – NReilingh Apr 28 '11 at 2:17
My issue is "that they be perceived as a single [...] phrase." – andyvn22 Apr 28 '11 at 2:30
Maybe I misused the word "phrase", if it means something else to more accomplished musicians. What I meant was quite like @Nreilingh's explanation. Please feel free to replace the word "phrase" with something more appropriate. – edgerunner Apr 28 '11 at 7:00
A phrase is a group of notes that forms a musical idea, which traditionally almost always runs over beat boundaries in a way that should cause breaks in the beaming. Maybe "beat or group of beats" would be more appropriate. – andyvn22 Apr 28 '11 at 21:30

Answering specifically on the 6/8 signature.

The rule given in the ABRSM is inspired from tradition and is sound in most cases.

In most "classical" music, this time signature was intended as a convenient way of notating triplets, especially in a suite of pieces with different signatures in a logic of diminution and augmentation or to match model dance rythms. You will find (for instance in Bach keyboard music) also 9/8 and 12/8 signatures that you should consider by default as having respectively 3 and 4 beats to a bar.

For a more recent (and now classical), very characteristic and liberal use of this look for instance at Beethoven sonatine (sonata) 25, opus 79 where the composer switches several times between 2/4 and 6/8 time signatures between episodes. A good player should respect the proportions of the time signatures.

-

Beaming per-beat is widely accepted as a standard; many sources would disagree with the decision to beam across two beats in 3/4. There are a lot of standards floating around--your best bet is to see what your specific "audience" prefers, be that certain performers or a teacher, pick a system, and be consistent. At some point, you'll probably develop a feeling for which system you feel is best.

But basically, you can't go too wrong by just always beaming into groups by beat.

-
I actually think that rule #1 specifies that it should be four and four. – Ben Alpert Apr 28 '11 at 0:36
This is true. Edited. – andyvn22 Apr 28 '11 at 0:42