Audio: singing (0:11)
singing sings a melody at four different tempos. The singing figure shows the score is in the key of A natural minor and uses all seven notes in the scale.
Singing is different to playing an instrument. The two main constraints in singing are tempo and the requirement to breathe.
The maximum tempo of singers is well below that of instruments. Unofficially, the world speed records for piano, guitar and violin are all somewhere around 1000bpm. This is nearly 20 notes per second and impressively fast. Top speed for a human is probably around 8 syllables per second, or in the region of 500bpm. This is only a guess because there is no official speed record for singing and a distinct lack of published information on the subject, but it is a reasonable guess.
To calculate your singing tempo, you might like to sing the magical word supercalifragilisticexpialidocious from the musical, Mary Poppins, written by the marvellous Sherman Brothers. It is one of the longest words in the English language and contains 34 letters arranged into 14 syllables. The first 12 syllables last one beat each and the final two syllables are 2 beats long each, making a total of 16 beats. Time yourself and divide by 16 to get your singing bpm. Congratulations if you get anywhere near 500bpm.
240bpm is a much more reasonable upper speed limit. It equates to four syllables per second. At an even more comfortable tempo of 120bpm, an eighth note, a quaver, is the minimum duration for a syllable of sung melody. You can then add bursts of sixteenth notes if you occasionally feel the need for speed.
There is a lower boundary to tempo as well as an upper speed limit. A listener has difficulty perceiving any rhythm lower than about 30bpm. A gap of two seconds between beats begins to destroy any notion of tempo. This places a maximum limit on the duration of a single syllable in a solo melody. It should be no more than a whole note, which has a duration of exactly two seconds at 120bpm.
Breathing is second nature to us. It affects singing to the extent that a human cannot breathe and sing at the same time. A singer needs time to catch their breath every now and again. The same also applies to a musician who plays a wind instrument although there are a gifted few who use circular breathing to draw air in through the nose, store it in the cheeks, and breathe it out through the mouth.
A person breathes between 12 and 18 times a minute on average. A typical single breath is thus about 4 seconds long on average. This sets a maximum limit for the duration of a group of related notes in a sung melody, equivalent to two bars of music in 4/4 meter at 120bpm.