How long does the music play in minutes and seconds?
You work out this figure from the metronomic tempo.
A metronome is a mechanical or electronic device capable of keeping perfect time.
Tempo is measured in beats per minute. Most music is between 40 and 210 beats per minute.
We write the metronomic tempo at the top of the first page of the musical score, under the title and above the time signature.
This example is designed to be played at 100 beats per minute. The beat is a crotchet. Crotchet = 100.
Minutes of playing time = Number of beats played divided by tempo. There are 3 measures and 4 beats to the measure so 12 beats played. Minutes playing time = 12 / 100 = 0.12. Seconds playing time =0.12 * 60 = 7.2. (Say 7 seconds of music)
In cut common time beats are measured in minims.
Seconds playing time = (2 * 5 * 60) / 100 = 6
2 beats to the bar
60 seconds to the minute
Tempo 100 beats per minute
In compound time the beat is a dotted crotchet. This music is designed to be played at 165 beats per minute.
Seconds playing time = (2 * 4 * 60) / 165 = 2.9
Some metronomic tempi are more common than others. Band leaders traditionally carry a watch with a second hand.
The second hand counts in the band. For example,
crotchet = 120 is march tempo.
March tempo is two beats per second.
Band leaders use their watch to accurately count in
|60||1 beat per second|
|120||2 beats per second - March Tempo|
|240||4 beats per second|
By counting 3 to every second, band leaders accurately count in 180 beats per minute and its derivatives 90 beats per minute and 45 beats per minute.
|180||3 beats per second|
|90||half the speed of 180|
|45||quarter the speed of 180|
Other tempi from a watch are close approximations. Try getting an accurate tempo of 100 from a watch!