This post is one of a 2-part series of free basic music theory lessons on my blog, musictheoryde-mystified.com. You can see the complete list here. Please feel welcome to make a comment or ask a question.
In 3. Beats, Tempo and Timing we saw that music is counted in beats – a bit like counting seconds, except that different pieces are counted faster or slower. How fast we count is indicated by the tempo.
We also saw that beats are grouped into bars, which act as a larger unit within the piece’s structure. These groups can be any length but are typically a few beats long.
The number of beats in a bar is written at the start of the first stave, in the form of a fraction without the dividing line. This is called the time signature.
A Time Signature Tells Us How to Count
In simple time, the time signature tells us two things. The numerator (the top number) indicates how many beats per bar and the denominator (bottom number) represents the fraction name of the note value used to represent 1 beat.
3 3 beats per bar
4 quarter note (crotchet) = 1 beat
TIP: Read this as “3 x 1/4 note beats per bar”
In the above example of 3/4, there are 3 beats per bar, where the quarter note (crotchet) = 1 beat. We count to 3 for each bar.
Of course the bars can be filled with notes of various lengths. The time signature indicates where the beats are and tells us how to count.
NOTE: A few time signatures, known as compound time, are interpreted differently. We will visit these in Part 2 of this course.
Common Time
The most popular time signature in modern times is 4/4, which is 4 crotchet beats per bar. It is so popular that it has a unique name, common time, and a shortcut symbol, the letter C.
4/4 and C are equally valid symbols – the choice is up to the composer.
X/4
The most frequently used time signatures use the crotchet to represent 1 beat, as in the above examples.
The fraction name for a crotchet is 1/4. For convenience, we can say that all these time signatures are in x/4, where x is the number of beats in the bar.
A time signature can have any number of beats but smaller numbers are more common. For longer time signatures we tend to mentally break them up into smaller groups. For instance, a bar of 7 beats could be thought of as 3+4 (or 4+3, depending on how the music flows, or even 3+2+2 etc.). Sometimes this is indicated in the music with an accent > symbol over the strong beats.
In general, though, bars tend to be fairly short, typically 2 to 4 beats per bar.
Simple Time
Simple time is an overall term encompassing all time signatures that can be read as a simple fraction, where the upper number represents the number of beats in a bar.
Of these, time signatures in x/4 are by far the most common, but the crotchet or 1/4 note isn’t the only note value that can represent 1 beat. Other note values can also be used, such as a quaver (1/8 note) or minim (1/2 note).
Although not covered in this basic course, these other time signatures work the same way as x/4: 4/8 = 4x 1/8 note (quaver) beats per bar and 3/2 = 3x 1/2 note (minim) beats per bar.
Halves and Quarters
In simple time, beats are easily divided into halves and quarters, the default rhythmic framework for many genres and styles. Even the note values themselves are designed to divide into halves and quarters – each symbol is half (or double) the length of the next.
The notes of an actual melody are usually a mixture of longer and shorter notes. Some of these are on a beat, others might start between beats. The time signature gives us a counting reference so we can interpret the notes correctly. Is a particular note on the beat or not, and on which beat within the bar?
Note: Most pieces have a single time signature throughout. However, some are made up of different sections with contrasting character. Each section can have its own time signature, like miniature pieces within the overall work. (Actually, it’s possible to change the time signature any time, or even change back and forth!)
The Rhythm of a Time Signature
A time signature has a built-in hierarchy of strong and weak points. The most obvious example of this is beat 1. When we count to music, it’s quite natural to emphasise the start of each bar, to help us keep track of where we are as we count. This also makes it easier to “feel” the beats within each bar rather than have to count numbers in your head.
Even when not counting aloud, musicians typically emphasise the first beat of each bar a little in their head as they play, so that it feels like the the start of a group.
Unless the bar is only 2 beats long, there’s room for a secondary emphasis part-way through the bar.
Being bipedal, humans have an affinity for two’s and halves. That’s why simple time is so popular. The most comfortable way to count is in two’s: strong, weak, strong, weak. At a pinch we can count in three’s but unless it’s quite fast, we prefer to feel it as 2+1: strong, weak, strong(ish).
To count in 4 we split it into 2+2, strong, weak, strong, weak. To feel like one group of 4, we make the first emphasis stronger than the second.
Time signatures have strong and weak beats, alternating where possible.
For example, in 4/4, beat 1 is the strongest of all, beat 3 a little less so but still strong, and beats 2 and 4 are weak.
A Beat Is Like a Miniature Bar of 4/4
Dividing up a beat is the same in miniature. The beat itself is the strongest, the 2nd quaver, halfway through, is the next strongest, and the other semiquavers, numbers 2 and 4, are the weakest.
Below, you can see and hear the hierarchy of the most common time signatures using bass guitar and drum kit sounds (the bass plays the strong beats and the snare plays the beats).
The more notes are on top of each other, the stronger the implied emphasis.
This is an exclusive preview of one of my custom illustrations from my upcoming music theory reference, Music Theory De-mystified, which I hope to complete by end 2023.
So What?
The implied rhythm of the time signature acts as a reference accompaniment which allows us to feel where the bars and beats are. Without this we wouldn’t be able to interpret the rhythm of the music correctly.
Have you heard the term “syncopation?” It’s where the rhythm is played with emphasis in unexpected places, typically between the beats rather than on them, or on the weak beats rather than the strong ones. It feels like it’s “against the grain”; like it’s competing with something – often in an exciting way!
We’ll visit this in more detail in a post down the track but the point is that syncopation feels “against the grain” or between the beats BEACAUSE OF the time signature. The implied accents of the beats and strong beats determined by the time signature is the competition.
That’s where the “in-between “ sensation of syncopation comes from; even if there is no instrument emphasising the beats we can still feel the implied rhythm of the time signature. We can feel the music skip between the beats when syncopated or work together with the beats when playing on the beat.
In the following example, the first bar is syncopated and the second bar is on the beat. Without being aware of the time signature, the first bar is hard to interpret until you hear the second bar following the beats. Once we’ve heard the 2nd bar, the rhythm of the first bar is easier to understand.
Now let’s listen with a metronome playing the bars and beats of the time signature.
Hearing the metronome, it’s much easier to work out the rhythm of the first bar.
In summary, think of the time signature as a default accompaniment to a melody. Melodies may or may not have a strong rhythmic quality in themselves but they will almost always be built around the framework of the time signature’s rhythmic hierarchy.
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NEXT LESSON: 7. Rest Values, How To Count Rests
PART 1 CONTENTS: Basic Music Theory Course Contents