time signatures

[forevere2]

12/8 is compound time

4 beats per measure
12 divisions and what else?

So does this mean that for a measure (bar), the sum of the duration is equal too... what?

[fencingfellow]

12/8 literally means 12 beats in a measure, and 8th notes get one beat.  Being a compound meter though, beats are commonly grouped to give a feel of fewer, perhaps 4 as you've mentioned, but 12/8 does not necessarily have 4 beats.  The beats can be grouped however a composer wishes.  Most common are 4+4+4, or 3+3+3+3, but there are by no means the only options.  6+6 sees some use, and in more modern works I've encountered things like 5+5+2.

As for your other question, about "the sum of the duration", I do not understand what you are asking.

[forevere2]

for the second part...

lets say that it was 4/4
So its 4 quarter notes per bar.
So that means that 4 quarter notes is the maximum that can be put into the measure.

So what's 12/8 equivalent to? 4 eighth notes?
Oh for compound time,  the numerator yields the number of divisions right? So that means that there should be a total of 4 beats, since compound time is divided into 3...

[abell88]

Oh for compound time,  the numerator yields the number of divisions right? So that means that there should be a total of 4 beats, since compound time is divided into 3...

Yes, 12/8 will commonly sound like 4/4 (with all triplets), although as mentioned above there are other possibilities.

[cjp_piano]

I always say the top number and then the kind of note for the bottom number.

4/4 = 4 quarters (per measure)

12/8 = 12 eighths

2/2 = 2 half notes

3/8 = 3 eighths

etc

Think of compound time as subdivided in triplets. 

Usually things like 6/8 9/8 and 12/8 are grouped in 3's.  So 6/8 is like 2 big beats with 3 eighth notes in each beat (2X3=6).   

9/8 is like 3 beats with 3 eighth notes in each beat.

12/8 is like 4 beats with 3 eighth notes in each beat.

[bernhard]

Time signatures have two different aspects.

The first one tells you how many of a certain note value “fill up” a bar.

So, as fencingfellow said, 12 / 8 means that 12 quavers (8th notes) will fill up a bar; 3 / 4 means that 3 crochets (quarter notes) fill up a bar.

However, there is another aspect of time signatures: it tells you the structure of accents in the bar. So, in 2 / 4, although there are two “beats” filled up by crochets or their equivalents, the first beat is strong, while the second beat is weak. In 3/4  the first beat is strong and the next two are weak (Um – pah – pah) and in 4 / 4 the first beat is strong, the third beat is strong but not as strong as the first, and the second and fourth beat are weak. These are the traditional time signatures (binary, ternary, quaternary).

Compound time signatures follow the same strong-weak beat structure as their simple counterparts: so 6/8 = 2/4; 9/8 = 3/4  and 12/8 = 4/4 as far as strong/weak beats are concerned. You can see that maths does not quite apply here.

You can rewrite any compound time signature into its simple time signature if you use triplets. So compound time signatures (as triplets for that matter) is a way to introduce division by 3 on note values, which otherwise would be confined by divisions by 2.

So, a 6/8 time signature which implies 6 quavers per bar and one strong and one weak beat, can be rewritten as 2/4 by replacing the three quavers with a quaver triplet (= 1 crochet) like so:

This piece by Mendelssohn (SWW no. 45) – originally in 6/8:



Could be rewritten in 2/4, using triplets instead of quavers, and the performance would be exactly the same.



A good example of two different maps for the same territory.

Best wishes,
Bernhard.

[martha argerrrrrich]

So, a 6/8 time signature which implies 6 quavers per bar and one strong and one weak beat, can be rewritten as 3/4 by replacing the three quavers with a quaver triplet (= 1 crochet) like so:


Best wishes,
Bernhard.

Bernhard, Could be a small typo....did u mean 6/8 to 2/4 instead of 3/4...although u gave a right example on Mendelsson....

[bernhard]

Bernhard, Could be a small typo....did u mean 6/8 to 2/4 instead of 3/4...although u gave a right example on Mendelsson....

Dang!

At least someone is reading my posts!

Thank you, I have corrected it.

Best wishes,
Bernhard.