<P> An overtone is any frequency greater than the fundamental frequency of a sound . Using the model of Fourier analysis, the fundamental and the overtones together are called partials . Harmonics, or more precisely, harmonic partials, are partials whose frequencies are integer multiples of the fundamental (including the fundamental which is 1 times itself). These overlapping terms are variously used when discussing the acoustic behavior of musical instruments . (See etymology below .) The model of Fourier analysis provides for the inclusion of inharmonic partials, which are partials whose frequencies are not whole - number ratios of the fundamental (such as 1.1 or 2.14179). </P> <P> When a resonant system such as a blown pipe or plucked string is excited, a number of overtones may be produced along with the fundamental tone . In simple cases, such as for most musical instruments, the frequencies of these tones are the same as (or close to) the harmonics . Examples of exceptions include the circular drum,--a timpani whose first overtone is about 1.6 times its fundamental resonance frequency, gongs and cymbals, and brass instruments . The human vocal tract is able to produce highly variable amplitudes of the overtones, called formants, which define different vowels . </P> <P> Most oscillators, from a guitar string to a flute, will naturally vibrate at a series of distinct frequencies known as normal modes . The lowest normal mode frequency is known as the fundamental frequency, while the higher frequencies are called overtones . Often, when an oscillator is excited by, for example, plucking a guitar string, it will oscillate at several of its modal frequencies at the same time . So when a note is played, this gives the sensation of hearing other frequencies (overtones) above the lowest frequency (the fundamental). </P> <P> Timbre is the quality that gives the listener the ability to distinguish between the sound of different instruments . The timbre of an instrument is determined by which overtones it emphasizes . That is to say, the relative volumes of these overtones to each other determines the specific "flavor" or "color" of sound of that family of instruments . The intensity of each of these overtones is rarely constant for the duration of a note . 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 . 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 . </P>

The collection of a fundamental pitch and its overtones is known as a(n)