Tone

The word tone is ambiguous because it has several meanings. The word tone often describes a physical phenomenon (a sound wave that is perceived to have a single, clear pitch) as opposed to a note, which is part of a musical score, and tends to be understood as an instruction to musicians.

Tone can also evoke other primary sensations such as pitch, loudness, timbre, and duration, which are subjective phenomena. They result from highly complex physical mechanisms occurring in the ear, and information-processing operations taking place in the nervous system. A tone is often described as having a different loudness (strength). Loudness, understood as a subjective sensation, is associated with the intensity or energy flow of a sound wave reaching the ear of a listener. Amplifying a sound increases both its intensity (the physical measure) and its loudness (the subjective attribute).

Further, a tone can refer to a unit of measure for the distance between two pitches, that is, two semitones make one tone. Pitch is described as the sensation of “height,” in the way that one might think of a tone in a musical line or melody as “higher” or “lower” than others. The sensation of pitch is strongly associated with the fundamental frequency of a tone, which is the number of oscillation patterns, or repeating events, per unit of time, and is most commonly measured in Hertz (Hz). For example, the A note on a violin string vibrates at about 440 Hz (440 vibrations per second). Higher frequencies correspond to higher pitches.

Performers often refer to the tone of their instruments, but more clearly they refer to the timbre, the quality or color of a tone. Timbre allows a listener to distinguish different instruments, even when playing the same pitch with the same loudness. The tone of instruments is often described in terms of very tactile adjectives such as soft, warm, raspy, or harsh.

One of the major studies on tone is the work by German physicist Hermann von Helmholtz (1885), whose theories on the perception of sound, and specifically on the sensation of tone, became highly influential. Helmholtz distinguished tone from noise, and defined a musical tone as a sound that “strikes the ear as perfectly undisturbed, uniform sound which remains unaltered as long as it exists.” Musical tones have regular motions, or periodic motions, and the sensation of tone is “due to a rapid periodic motion of the sonorous body,” whereby these motions reach the human ear through wave-like vibrations in the air.

The etymology of the word tone implies “stretching.” It stems from the Latin term tonus, or the Greek tonos, which is a “sound,” an “accent,” or a “vocal pitch,” but also implies the idea of “stretching,” such as in a taut string. In medieval times, tone was particularly understood as relating to music, and only in the 1600s was tone used as in the sense of tone as a manner of speaking.

Tone is delineated from the concept of noise because noise does not tend to be described in terms of timbre or pitch, although it may be said that noises can have different timbres, and noises carry a certain loudness or intensity.

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