String harmonic

Playing a string harmonic (a flageolet) is a string instrument technique that uses the nodes of natural harmonics of a musical string to isolate overtones. Playing string harmonics produces high pitched tones, often compared in timbre to a whistle or flute. Overtones can be isolated "by lightly touching the string with the finger instead of pressing it down" against the fingerboard (without stopping). For some instruments this is a fundamental technique, such as the Chinese guqin, where it is known as fan yin (泛音, lit. "floating sound"), and the Vietnamese đàn bầu.

Playing a string harmonic (a flageolet) is a string instrument technique that uses the nodes of natural harmonics of a musical string to isolate overtones. Playing string harmonics produces high pitched tones, often compared in timbre to a whistle or flute. Overtones can be isolated "by lightly touching the string with the finger instead of pressing it down" against the fingerboard (without stopping). For some instruments this is a fundamental technique, such as the Chinese guqin, where it is known as fan yin (泛音, lit. "floating sound"), and the Vietnamese đàn bầu. ==Overtones== When a string is plucked or bowed normally, the ear hears the fundamental frequency most prominently, but the overall sound is also colored by the presence of various overtones (frequencies greater than the fundamental frequency). The fundamental frequency and its overtones are perceived by the listener as a single note; however, different combinations of overtones give rise to noticeably different overall tones (see timbre). A harmonic overtone has evenly spaced nodes along the string, where the string does not move from its resting position. ==Nodes== The nodes of natural harmonics are located at the following points along the string, matching the Harmonic series. Harmonic interval names are given from Huygens-Fokker institute list of intervals . Above, the length fraction is the point, with respect to the length of the whole string, the string is lightly touched. It is expressed as a fraction , where m is the mode (2 through 18 are given above), and n the node number. The node number for a given mode can be any integer from 1 to . However, certain nodes of higher harmonics are coincident with nodes of lower harmonics, and the lower sounds overpower the higher ones. For example, mode number 4 can be fingered at nodes 1 and 3; it will occur at node 2 but will not be heard over the stronger first harmonic. Ineffective nodes to finger are not listed above. The fret number, which shows the position of the node in terms of half tones (or frets on a fretted instrument) then is given by: F = \log_s \frac{m}{m-n} With s equal to the twelfth root of two, notated s because it's the first letter of the word "semitone". ==Guitar== There are a few harmonic techniques unique to guitar. ===Pinch harmonics=== A pinch harmonic (also known as squelch picking, pick harmonic, or squealy) is a guitar technique to achieve artificial harmonics in which the player's thumb or index finger on the picking hand slightly catches the string after it is picked, canceling (silencing) the fundamental frequency of the string, and letting one of the overtones dominate. This results in a high-pitched sound which is particularly discernible on an electrically-amplified guitar as a "squeal". Zakk Wylde (Ozzy Osbourne guitarist) is best known for this sound. ===Tapped harmonics=== Tapped harmonics were popularized by Eddie Van Halen. This technique is an extension of the tapping technique. The note is fretted as usual, but instead of striking the string the excitation energy required to sound the note is achieved by tapping at a harmonic nodal point. The tapping finger bounces lightly on and off the fret. The open string technique can be extended to artificial harmonics. For instance, for an octave harmonic (12-fret nodal point) press at the third fret, and tap the fifteenth fret, as . ===String harmonics driven by a magnetic field=== This technique is used by effect devices producing a magnetic field that can agitate fundamentals and harmonics of steel strings. There are harmonic mode switches as provided by newer versions of the EBow and by guitars built in sustainers like the Fernandes Sustainer and the Moog Guitar. Harmonics control by harmonic mode switching and by the playing technique is applied by the Guitar Resonator where harmonics can be alternated by changing the string driver position at the fretboard while playing. ==See also== 3rd bridge ==References==

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