Time Signatures: What They Mean & How to Use Them
To understand time signatures first you need to understand what tempo and musical notes represent in terms of time. Then you need to understand what measures are.
Let’s start with tempo…
In short, tempo tells you how fast to play a piece of music by telling you how many beats you can play per minute. But… what does that mean?
If you’ve ever looked at a piece of sheet music before at the top right-hand corner of the sheet you’ve probably seen a musical note beside an equals sign followed by a number. That number is the tempo of the song. The tempo of a song is divided into beats per minute (bpm). The most common tempo is called ‘Moderato’ (or moderate in English) and it’s value is 120bpm, although there are many other tempos to play a song at. What is a beat? I’m glad you asked!
Let’s move on to musical notes…
A ‘beat’, in this sense, is represented by a musical note that has a particular value expressed by a fraction. When thinking about musical notes in terms of time there are four common values: whole notes (1), half notes (1/2), quarter notes (1/4), and eighth notes (1/8). The beat in in of itself doesn’t have a note value. In other words, the composer of the song gets to decide which note ‘gets the beat’. Commonly, a quarter note is used to represent the value of each ‘beat’ in a song (i.e. 1 quarter note = 1 beat). Once you’ve decided which note will be used as the baseline ‘beat’, then you get to decide how long that note will last in seconds in your song…
Back to tempo!
Bear with me here, we are going to have to do some math. The tempo value of a song tells us how many ‘beats’ can be played per minute. So, if the song’s tempo is 120bpm then in this song each beat is 0.5 second long (Here’s the math: seconds per minute/beats per minute=seconds per beat so 60/120=0.5). Now that you know each respective ‘beat’ in this song counts for one quarter note, you know that a quarter not in this song is played for 0.5 seconds. If you scroll up and look at the chart above you will understand why we use fractions to show the value of musical notes and not seconds. By using fractions musicians gain the flexibility to change the speed of any and every piece of music by changing the length of time the notes are played for… while keeping how long each of the notes are played in relation to each other the same. So where was I going with all this? Ah, yes! Time signatures.
But first… measures…
You might have heard them called both bars and measures before… they mean the same thing. To reduce the mental load of reading and writing music the notes of a song are divided into sections called measures or bars, that look like this…
What goes inside of each measure of music is indicated by the composer to the reader by time signatures.
And finally time signatures…
Time signatures tell us how many beats of music there are per measure and which musical note represents a single ‘beat’ in the particular song. With the help of time signatures and tempo you can say two important things with certainty:
- Which note the beat is on (whole, half, quarter, eighth, etc…)
- How long to hold each beat in said song (in seconds)
So let’s put this to the test. If your song is in common time it’s time signature is 4/4 and it’s tempo is 120bpm. The top 4 in your time signature tells you that there are 4 beats per measure. The bottom 4 in your time signature tells you that the beat is on the quarter note… therefore in your song there are 4 quarter notes per measure. Moreover, since the beat in your song is on the quarter note and your song’s tempo is 120bpm (beats per minute)… there are 120 quarter notes per minute in your song. Therefore each “beat” or quarter note in your song should be held for 0.5 seconds… and by extension each half note should be held for 1.0 second and each whole note for 2 seconds and so on…
And there you have it! Time signatures as well as a few other important concepts in basic music theory explained!
Please comment with any questions, I’d love to hear your thoughts! :)
