Tempo

(Latin: tempus = time) Plural: tempi or tempos. The speed of music or any sequence of sounds. Traditional tempo indications are given in Italian, ranging (slow to fast): largo, adagio, andante, moderato, allegro, presto, prestissimo. Precise speeds are indicated by metronome markings, giving the number of beats per minute. Sixty to eighty beats per minute corresponds to a normal human pulse rate or walking speed.

See: Note, Rhythm, Tempophone.

Considerable involuntary physiological reaction is related to tempo, most notably the pulse rate, blood pressure and respiration rate. This fact is exploited by Muzak, or background music, to manipulate the individual's work capacity, sense of time and purchasing attitude. See: Moozak.

A study of tempi and cycles found in the acoustic environment is an extremely important aspect of soundscape studies and a fundamental principle of soundscape design. The speed-up of basic human rhythms mechanically and electrically has resulted in the drone and hum, and other stationary sounds, which are devoid of the rhythm and contrast of natural sound patterns, and are most likely to be tension-producing. A well-balanced soundscape will exhibit a complex interplay of tempi and rhythms. Compare: Sound Pollution.

The acoustic rhythms of the natural environment (with some technological intrusions) are shown in the diagrams below. The daily cycle is from field observations by the World Soundscape Project, whereas the annual cycle was compiled from information supplied by biologists.

Sound log of a 24-hour period at a rural site at mid-summer.

Annual cycle of rhythms in the natural soundscape of British Columbia.