An overtone is a natural resonance or vibration frequency of a system. Systems described by overtones are often sound systems, for example, blown pipes or plucked strings.

Approximate harmonic overtones on a string

If such a system is excited, a number of sound frequencies may be produced. In Acoustics and Telecommunication, the harmonic of a Wave is a component Frequency of the signal that is an Integer These frequencies, are usually, but not always, a close approximation to an integer multiple of a lowest resonance frequency. Thus, overtones and harmonics should not be confused or interchanged. By definition a harmonic is an exact integer multiple of a fundamental frequency, whereas in most systems, overtones are never exact integer multiples of a root frequency. In Acoustics and Telecommunication, the harmonic of a Wave is a component Frequency of the signal that is an Integer For example, the first overtone of a circular drum is approximately 2. 4 times its fundamental resonance frequency.

Explanation

Most oscillators, from a guitar string to a bell (or even the hydrogen atom or a periodic variable star) will naturally vibrate at a series of distinct frequencies known as normal modes. A hydrogen atom is an atom of the chemical element Hydrogen. The electrically neutral For the astronomical object see Variable star. Variable Star is a 2006 novel written by Spider Robinson A normal mode of an oscillating system is a pattern of motion in which all parts of the system move sinusoidally with the same frequency The lowest normal mode frequency is known as the fundamental frequency, while the higher frequencies are called overtones. The fundamental tone, often referred to simply as the fundamental and abbreviated fo, is the lowest frequency in a harmonic series. Often, when these oscillators are excited, by, for example, plucking a guitar string, it will oscillate at several of its modal frequencies at the same time. In music, this gives the sensation of hearing other frequencies (overtones) above the lowest frequency (the fundamental). The overall combination of the instrument's specific overtones is what determines the timbre ("flavor" or "colour" of sound) of that instrument. In Music, timbre (ˈtæm-bər' like timber, or, from Fr timbre tɛ̃bʁ is the quality of a Musical note or sound that distinguishes different 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.

A driven non-linear oscillator, such as the human voice, a blown wind instrument, or a bowed violin string (but not a struck guitar string or bell) will oscillate in a periodic, non-sinusoidal manner. This generates the impression of sound at integer multiple frequencies of the fundamental known as harmonics. In Acoustics and Telecommunication, the harmonic of a Wave is a component Frequency of the signal that is an Integer For most string instruments and other long and thin instruments such as a trombone or bassoon, the first few overtones are quite close to integer multiples of the fundamental frequency, producing an approximation to a harmonic series. See Harmonic series (mathematics for the (related mathematical concept Thus, in music, overtones are often called harmonics. Depending upon how the string is plucked or bowed, different overtones can be emphasized.

However, some overtones in some instruments may not be of a close 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. In fact, the flared end of a brass instrument is not to make the instrument sound louder, but to correct for tube length “end effects” that would otherwise make the overtones significantly different from integer harmonics. This is illustrated by the following:

Consider a guitar string, its idealised 1st overtone would be exactly twice its fundamental if its length was shortened by ½, say by lightly pressing a guitar string at the 12th fret. However, if a vibrating string is examined, it will be seen that the string does not vibrate flush to the bridge and nut, but has a small “dead length” of string at each end. This dead length actually varies from string to string, being more pronounced with thicker and/or stiffer strings. This means that halving the physical string length, does not halve the actual string vibration length, and hence, the overtones will not be exact multiples of a fundamental frequency. The effect is so pronounced that well set up guitars will angle the bridge such that the thinner strings will progressively have a length up to few millimeters shorter than the thicker strings. Not doing so would result in inharmonious chords made up of two or more strings. Similar considerations apply to tube instruments.

The intensity of each of the overtones is rarely constant during the duration of the overall sound. Over time, different overtones may decay at different rates causing the relative intensity of each overtone to 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 the timbre of a note may be perceived differently when played staccato or legato, dampened or lengthened. In Musical notation, the Italian word staccato (literally detached, plural staccatos or staccati) indicates that notes In Musical notation the Italian word legato (literally meaning "tied together" indicates that musical notes are played or sung smoothly

Musical usage term

An 'overtone' is a partial (a "partial wave" or "constituent frequency") that can be either a harmonic or an inharmonic. In Acoustics and Telecommunication, the harmonic of a Wave is a component Frequency of the signal that is an Integer In music inharmonicity is the degree to which the frequencies of Overtones (known as partials partial tones or Harmonics depart from whole A harmonic is an integer multiple of the fundamental frequency. In Acoustics and Telecommunication, the harmonic of a Wave is a component Frequency of the signal that is an Integer An inharmonic overtone is a non-integer multiple of a fundamental frequency. In music inharmonicity is the degree to which the frequencies of Overtones (known as partials partial tones or Harmonics depart from whole

An example of harmonic overtones: (absolute harmony)

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. In Music, sharp means higher in pitch More specifically in Musical notation, sharp means "higher in pitch by a Semitone (half step" In Music, flat means "lower in pitch" More specifically in Music notation, flat means "lower in pitch by a Semitone 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. A tuning fork is an acoustic Resonator in the form of a two-pronged Fork with the tines formed from a U-shaped bar of elastic The flute is a Musical instrument of the Woodwind family Unlike other woodwind instruments a flute is a Reedless wind instrument that produces its

Type of music

In barbershop music, the word overtone is often used in a different (though related) way. Barbershop Vocal harmony, as codified during the barbershop revival era (1940s-present is a style of A cappella, or unaccompanied Vocal music characterized 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. Psychoacoustics is the study of subjective human Perception of Sounds Alternatively it can be described as the study of the Psychological correlates 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). Similar effects can be found in other a cappella polyphonic music such as the music of the Republic of Georgia. Georgia ( საქართველო, Sakartvelo) is a Transcontinental country in the Caucasus region situated at the dividing line between

String instruments

String instruments can also produce multiphonic tones when strings are divided in two pieces. The most developed instrument for playing multiphonic tones is the Sitar in which there are sympathetic strings which help to bring out the overtones while one is playing. The sitar ( Hindi: सितार Urdu: ستار Persian: سی تار) is a Plucked stringed instrument. The most well-known technique on a guitar is playing flageolet tones. In Acoustics and Telecommunication, the harmonic of a Wave is a component Frequency of the signal that is an Integer Other multiphonic extended techniques used are prepared piano and prepared guitar. Extended techniques are performance techniques used in Music to describe unconventional unorthodox or "improper" techniques of Singing, or of A prepared piano is a Piano which has had its sound altered by placing objects (preparations between or on the strings or on the hammers or dampers A prepared guitar is a Guitar which has had its Timbre altered by placing various objects on or between the instrument's strings including other Extended

Overtone singing

Overtone singing, also called harmonic singing, occurs when the singer amplifies voluntarily two overtones in the sequence available given the fundamental tone he/she is singing. Overtone singing, also known as throat singing, overtone chanting, or harmonic singing, is a type of singing in which the Singer manipulates Overtone singing is a traditional form of singing in many parts of the Himalayas and Altay; Tibetans, Mongols and Tuvans are known for their overtone singing. Also, harmonics change the overtones.

Jew's harp

A similar technique is used for playing the Jew's harp: the performer amplifies the instrument's overtones by changing the shape, and therefore the resonance, of their mouth. The Jew's harp, juice harp, jaw harp, mouth harp, Ozark harp, or marranzano pancake is thought to be one of the oldest Musical Acoustic resonance is the tendency of an acoustic system to absorb more energy when the Frequency of its oscillations matches the system's natural frequency of vibration

See also

• Harmonic series (music)
• Just intonation
• Xenharmonic
• Stretched octave
• Combination tone

External links

• An illustration of standing waves as overtones on a violin string
• Calculations of harmonics and overtones from fundamental frequency
• Overtone - South African Music Portal