part0012

Students often assume that 1 beat takes 1 second of clock time, but this is incorrect. When we created a quarter note pulse in the last lesson, we did not conclude that one beat would be played for any specific number of seconds. The actual time it takes to play a beat is determined by tempo . The word tempo is the musical term for pace (or speed). If the tempo is quick, the beats are shorter because they are closer together, and if the tempo is slower, the beats are longer because they are further apart from each other.

Before we proceed, please keep in mind that tempo doesn’t affect the relative durations of the notes. For example, the half note is still and always will be twice as long as the quarter note no matter how fast or slow they are played.

To indicate what the tempo is, composers write specific musical terms at the beginning of the music. As from the Romantic era (c.1810 to 1910), composers used terms in their own languages, but in earlier times it was traditional to use terms in Italian. This is because Italy was the place where classical music began to flourish back in the Renaissance.

These terms are still in use today. For example, the Italian word allegro is an indication that the music should be played quickly. And the term lento is Italian for slow. A problem that arises with these terms, however, is that although we know that allegro means quickly and lento means slowly, we don’t really know exactly how quick or how slow.

Johann Maelzel (1772 – 1838) solved this problem with the invention of the metronome. The job of his device is to make a click sound (or a beep if it’s a modern electronic or digital version) at any tempo we choose. Every one of those clicks represents a beat and so it makes an audible pulse.

Let’s get a quick feel for the difference between two different tempos. Listen to audio example 3.1 . This is 120 beats per minute on the metronome. Now listen to audio example 3.2 . This is a composition by Mozart played at around this same tempo.

Now compare that to the tempo of 70 bpm on the metronome–audio example 3.3 . And listen to the 2nd movement of the same piece by Mozart played around the same tempo–audio example 3.4 . As you can hear, tempo is a significant influence on the character of the music.

Here is a table of the 6 most common Italian terms for tempo, their meaning, and their equivalent beats per minute.

Note that in practice, these terms represent a range of tempos and not strictly one speed. Adagio is listed as 60 bpm, but it could also be 54 or 68 bpm. Allegro is listed as 120 bpm, but it could also be 116 or 126 bpm. The exact tempo always depends on context. You can hear examples of this anytime you listen to the same piece played by different musicians. The tempos vary according to their interpretation of the composer’s ideas.

For a tempo marking to be accurate, it’s not enough to know the number of beats per minute. We also need to know what those beats are worth. Are they quarter note beats? Half note beats? Eighth note beats? Something else? In the last lesson, we learned that the pulse consists of recurring beats and that those beats must be assigned a note value.

So the complete marking of tempo consists of two parts: the value of each beat (such as quarter notes or half notes) and the number of beats per minute.

For example, here we have “100 quarter note beats per minute”. This means that the pulse consists of quarter notes and there are exactly 100 of them in a minute.

Here is another example. This one is “80 half note beats per minute” . It means that the pulse consists of half notes and there are exactly 80 of them in a minute.