Overtone

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An overtone is a sinusoidal component of a waveform, of greater frequency than its fundamental frequency. The term is usually used in music, rather than wave physics. (see standing wave)

1 Explanation
2 Musical usage term
3 Type of music
4 See also
5 External links

[edit] Explanation

When a string on a musical instrument is plucked it creates various vibration patterns that are a composite of standing waves unique to the string's physical characteristics, such as: length, mass per unit length, and tension.

In string instruments, when plucking a single string, we say we are playing "a single note" (fundamental frequency) yet the string also emits several tones of a higher frequency (pitch), called overtones. This is an unavoidable physical phenomenon of waves in matter. (not just strings)

It is the frequency of the overtone with the greatest amplitude that determines the note that we hear most prominently (Almost always it is the fundamental frequency itself), and the overall combination of the instrument's specific overtones is what determines the timbre ("flavour of sound") of that instrument. Timbre is what gives the listener the ability to distinguish different instruments that play the same note at the same volume in a band or orchestra.

For most western music instruments, the first few overtones are integer multiples of the fundamental frequency, thus producing a perfect harmonic series. Depending upon how the string is plucked or bowed, different harmonics can be emphasized. The higher overtones almost always have amplitudes (volume) much less than the fundamental.

However, some overtones in some instruments may not be of an exact integer multiplication of the fundamental frequency, thus causing a small dissonance. "High quality" instruments are usually built in such a manner that their individual notes do not create disharmonious overtones.

The intensity of each of the overtones is rarely constant during the duration of the overall sound. Over time, the intensity of each overtone may rise or fall independent of the overall volume of the sound, and a carefully trained ear can hear these changes even in a single note. This is why a note may sound differently when played staccato or legato, dampened or lengthened.

[edit] Musical usage term

An 'overtone' is a partial (a "partial wave" or "constituent frequency") that can be either a harmonic or an inharmonic. A harmonic is an integer multiple of the fundamental frequency. An inharmonic overtone is a non-integer multiple of a fundamental frequency.

An example of harmonic overtones: (absolute harmony)

f	440 Hz	fundamental tone	first harmonic
2f	880 Hz	first overtone	second harmonic
3f	1320 Hz	second overtone	third harmonic
4f	1760 Hz	third overtone	fourth harmonic

Not all overtones are necessarily harmonics, or exact multiples of the fundamental frequency. Some musical instruments produce overtones that are slightly sharper or flatter than the true harmonics. The sharpness or flatness of their overtones is one of the elements that contributes to their unique sound. This also has the effect of making their waveforms not perfectly periodic. Some instruments, such as tuning forks or flutes produce a clear or near perfect sound because their overtones are in very good approximation of "absolute" harmony with the base frequency.

[edit] Type of music

In barbershop music, the word overtone is often used in a different (though related) way. It refers to a psychoacoustic effect in which a listener hears an audible pitch that is higher than, and different from, the four pitches being sung by the quartet. This is not a standard dictionary usage of the word "overtone." The barbershopper's "overtone" is created by the interactions of the overtones in each singer's note (and by sum and difference frequencies created by nonlinear interactions within the ear).

Overtone singing, also called harmonic singing, occurs when the singer amplifies voluntarily one overtone in the sequence available given the fundamental tone he/she is singing. Overtone singing is a traditional form of singing in many parts of the Himalayas; Tibetans, Mongols and Tuvans are known for their overtone singing.