Measures and Time Signatures

Measures are indicated in the music staff by a vertical line. They are useful for maintaining organization in a piece. How many notes and rests that are allowed in each measure is indicated by the time signature or the meter at the beginning of the measure. The time (or meter) signature is placed after the clef on the staff. The time signature is effective for all the following measures until a new time signature is introduced in the piece.

Simple Meters

Common time or 4/4 time (otherwise known as simple quadruple – the simple indicates that the notes can be broken down into halves, so a quarter note can be broken down into eighths), indicates that four quarter-note beats are allowed in the measure. This means that four beats of any combination of notes and rests are allowed. Common time is used often in classical, rock, jazz, country, and bluegrass music.
Common time:
4/4 time:

3/4 time (otherwise referred to as simple triple, three beats that can be divided into halves) means that three quarter-note beats are allowed in the measure. This time signature is used mainly in waltzes. As you can probably see, the top number in a time signature indicates how many beats are allowed in the measure and the bottom note indicates what type of beat the top number is referring to. In the examples given, the 4 indicates a quarter-note beat. We will see in further examples what other numbers would mean.

2/2 time (simple duple, two beats that can be divided into halves). This time signature is seen often in marches.

So now you see that the 2 indicates half-note beats. The general rule is that if you separate the top note from the bottom note like you would in Mathematics with fractions, you get the top number (which indicates the number of beats) and the fraction with the bottom number, which shows you what kind of beat is involved.

Compound Meters

The previous examples have all been simple meters, allowing all the notes to be divided into halves. Compound meters allow the notes to be divided into triples. Looking back at 6/8 we see that the six eighth notes can be organized into either two compound duples or three simple triples. The compound duples have the dotted eighth as the “larger beat” and the compound duples have a meter similar to that of ¾. Compound duples will always have a 6 in the top of the time signature.

It is also possible to keep going and create compound triples with 9 beats on the top and compound quadruples with 12 beats on the top.

Odd Meters

Odd meters include both compound and simple beats. For example: 5/8 contains a simple (two eighth notes makes one quarter) and a compound (three eighth notes make a dotted quarter). It is up to the composer to decide which grouping comes first, either way, the meter is still 5/8.
Another example is 7/8, where one would count: 1-2-1-2-1-2-3 with two simple beats and one compound. Again, the order of the groupings does not matter, so the counting can go 1-2-3-1-2-1-2 or 1-2-1-2-3-1-2.
You may be thinking that it is only the odd numbers in the meter that make for odd meters, however, this is not the case. For example: 8/8 is formed with two compound beats and one simple beat. It looks like 4/4 with simple quadruple beats, but in 8/8 the larger beats should fall on two dotted quarters and a quarter.

Here is and example from Dave Brubeck's jazz piece Take Five:

Tenuto Ties

Tenuto ties are used in music to connect note durations that stretch across two or more measures. This is not necessary for rests since you do not stop resting (or break the silence) when you read from one rest to another. However, there is usually a short stop associated with the ending of one note and the beginning of another, even if the two notes have the same pitch. Thus, ties are used.