Damian Oxborough <[log in to unmask]> writes:

>As far as X/3 time signatures are concerned, non of the technical postings
>I've read have made any sense at all.  If a "2" is a quantity of minims
>and a "4" is a quantity of crotchets, then surely X/3 indicates a quantity
>of dotted-crotchets per bar.

Not so; you're confusing numerators with denominators.

(quick translation guide for those people who always need reminding, like
me:  semibreve = whole note, minim = half note, crotchet = quarter note,
quaver = eighth note)

Let's say that each semibreve is 2.4 seconds long (this will make the math
come out even).

X/2 means that you're dividing a semibreve into two parts, i.e., minims.
Each minim is 2.4/2 = 1.2 seconds long.

X/4 means that you're dividing a semibreve into four parts, i.e.,
crotchets.  Each crotchet is 2.4/4 = 0.6 seconds long.

X/3 means that you're dividing a semibreve into three parts, i.e., minim
triplets.  Each of these is 2.4/3 = 0.8 seconds long.

A dotted crotchet, on the other hand, has a length of one and a half times
a crotchet = 0.6 * 1.5 = 0.9 seconds long.

Putting these in ascending order of length:

crotchet = 1/4 semibreve
dotted crotchet = 3/2 * crotchet = 3/8 semibreve
minim triplet = 1/3 semibreve
minim = 1/2 semibreve

As you can see, the 3 is in the numerator, not the denominator, for a
dotted crotchet.

As you note, and as I've said before, in general it doesn't make much sense
to use a multiple of three in a denominator, since we already have time
signatures such as 6/8 and 9/8 to deal with those situations (we just make
dotted crotchets, rather than crotchets, the 'fundamental time unit', which
makes them easy to divide into three).

The place where it might make sense is where the prevailing time signature
is a power of 2 and there is a single measure which has a non-multiple-of-3
number of triplets in it.  I previously mentioned a rock song by the group
Soundgarden with this property, but got a couple of details wrong, so I'll
take this opportunity to correct them:  the name of the song is "Pretty
Noose", and the irregular measure is effectively 5/12 (five quaver
triplets), not 5/6 as I originally stated.

Dan Schmidt | http://www.dfan.org