Guitar harmonics
Encyclopedia
A guitar harmonic is a musical note
played by preventing or amplifying vibration
of certain overtones of a guitar
string.
Music using harmonic
s can contain very high pitch
notes difficult or impossible to reach by fret
ting. Guitar harmonics also produce a different sound quality than fretted notes, and are one of many techniques used to create musical variety.
sound wave feedback of a guitar amplifier at high volume, which causes an "infinite" vibration of certain
string harmonics. A third method, magnetic string drivers like the EBow, can generate string harmonics.
Harmonics are most often played by lightly placing a finger on a string at a nodal point
of one of the overtones at the moment when the string is driven. The finger immediately damps
all overtones that do not have a node near the location touched. The lowest-pitch overtone dominates the resulting sound.
When a guitar string
is plucked normally, the ear tends to hear the fundamental frequency
most prominently, colored by the presence of integer multiples of that frequency. The lowest frequency of vibration along the entire length of the string is known as the fundamental, while higher frequencies are referred to as overtone
s. The fundamental and overtones, when sounded together, are perceived by the listener as a single tone, though the relative prominence of the frequencies varies among instruments, contributing to timbre
. A harmonic overtone has evenly spaced nodes
along the string, where the string does not move from its resting position.
of natural harmonics are located at the following points along a guitar's neck. Note that for fretted strings, these locations shift up the fingerboard by the same number of frets, and resulting harmonics are called artificial harmonics.
The above fret numbers can be calculated:
where
, the frequency ratio of one musical half-step (i.e. one fret), 
is the mode number (1-10 are given above), and 
is the node number for that mode (
to 
).
Note that 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.
A pinch harmonic is produced by lightly touching the thumb of the picking hand against the string immediately after it is picked. This action is sufficient to silence the fundamental
and all overtone
s except those that have a nodes
at that location. This is generally accomplished by holding the plectrum
so very little of its tip protrudes between the thumb and forefinger (roughly 3–5 mm), allowing the thumb to brush the string immediately after it is picked.
The technique must be performed at one of the appropriate harmonic nodes for the note to sound. For example, to produce a pinch harmonic one octave
higher than the fundamental of a string that is stopped at the third fret of a guitar, the string must be plucked halfway between the third fret and the bridge (the 15th fret, as the neck is logarithmic). Other overtones of the same fundamental note may be produced in the same way at other nodes along the string. The point where the string is plucked therefore varies depending on the desired note. Most harmonics have several accessible nodes evenly spaced on the string, so the nodes used in practice are normally around where the string is normally picked (around the pickups on an electric guitar), rather than those above the neck as these are the easiest to access with the picking hand from normal playing.
Overtones with a frequency of a multiple of the intended overtone (i.e., the same note in a higher octave) will share the nodes of the lower overtones, so won't be muted. They will, however, be at a much lower volume and since they are the same note in a higher octave, don't detract from the sound of the note. If the string is pinched at the antinode
of the intended overtone, no higher overtones will sound.
A single harmonic overtone is quieter than a normal note, which contains many overtones. For this reason, guitar players often increase the guitar volume to play harmonics. Thicker strings, stronger pickups and adjustment to amplifier settings (increasing gain) are some ways of doing this. Note that when the string vibrates primarily at a single fundamental, it has different volumes through different pickups, depending on the proximity of nodes or antinodes to the pickup. The different overtone volumes are why neck and bridge pickups sound different. If a node is directly over a pickup, little or no sound is heard.
. Tapped harmonics
are 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 12+3=15.
and harmonics of steel strings. There are harmonic mode switches as provided by newer versions of the
Ebow and by guitar build 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.
Note
In music, the term note has two primary meanings:#A sign used in musical notation to represent the relative duration and pitch of a sound;#A pitched sound itself....
played by preventing or amplifying vibration
Vibration
Vibration refers to mechanical oscillations about an equilibrium point. The oscillations may be periodic such as the motion of a pendulum or random such as the movement of a tire on a gravel road.Vibration is occasionally "desirable"...
of certain overtones of a guitar
Guitar
The guitar is a plucked string instrument, usually played with fingers or a pick. The guitar consists of a body with a rigid neck to which the strings, generally six in number, are attached. Guitars are traditionally constructed of various woods and strung with animal gut or, more recently, with...
string.
Music using harmonic
Harmonic
A harmonic of a wave is a component frequency of the signal that is an integer multiple of the fundamental frequency, i.e. if the fundamental frequency is f, the harmonics have frequencies 2f, 3f, 4f, . . . etc. The harmonics have the property that they are all periodic at the fundamental...
s can contain very high pitch
Pitch (music)
Pitch is an auditory perceptual property that allows the ordering of sounds on a frequency-related scale.Pitches are compared as "higher" and "lower" in the sense associated with musical melodies,...
notes difficult or impossible to reach by fret
Fret
A fret is a raised portion on the neck of a stringed instrument, that extends generally across the full width of the neck. On most modern western instruments, frets are metal strips inserted into the fingerboard...
ting. Guitar harmonics also produce a different sound quality than fretted notes, and are one of many techniques used to create musical variety.
Technique
Harmonics are mainly generated manually by different playing techniques. Another method issound wave feedback of a guitar amplifier at high volume, which causes an "infinite" vibration of certain
string harmonics. A third method, magnetic string drivers like the EBow, can generate string harmonics.
Harmonics are most often played by lightly placing a finger on a string at a nodal point
Node (physics)
A node is a point along a standing wave where the wave has minimal amplitude. For instance, in a vibrating guitar string, the ends of the string are nodes. By changing the position of the end node through frets, the guitarist changes the effective length of the vibrating string and thereby the...
of one of the overtones at the moment when the string is driven. The finger immediately damps
Damping
In physics, damping is any effect that tends to reduce the amplitude of oscillations in an oscillatory system, particularly the harmonic oscillator.In mechanics, friction is one such damping effect...
all overtones that do not have a node near the location touched. The lowest-pitch overtone dominates the resulting sound.
Overtones
Strings (music)
A string is the vibrating element that produces sound in string instruments, such as the guitar, harp, piano, and members of the violin family. Strings are lengths of a flexible material kept under tension so that they may vibrate freely, but controllably. Strings may be "plain"...
is plucked normally, the ear tends to hear the fundamental frequency
Fundamental frequency
The fundamental frequency, often referred to simply as the fundamental and abbreviated f0, is defined as the lowest frequency of a periodic waveform. In terms of a superposition of sinusoids The fundamental frequency, often referred to simply as the fundamental and abbreviated f0, is defined as the...
most prominently, colored by the presence of integer multiples of that frequency. The lowest frequency of vibration along the entire length of the string is known as the fundamental, while higher frequencies are referred to as overtone
Overtone
An overtone is any frequency higher than the fundamental frequency of a sound. The fundamental and the overtones together are called partials. Harmonics are partials whose frequencies are whole number multiples of the fundamental These overlapping terms are variously used when discussing the...
s. The fundamental and overtones, when sounded together, are perceived by the listener as a single tone, though the relative prominence of the frequencies varies among instruments, contributing to timbre
Timbre
In music, timbre is the quality of a musical note or sound or tone that distinguishes different types of sound production, such as voices and musical instruments, such as string instruments, wind instruments, and percussion instruments. The physical characteristics of sound that determine the...
. A harmonic overtone has evenly spaced nodes
Node (physics)
A node is a point along a standing wave where the wave has minimal amplitude. For instance, in a vibrating guitar string, the ends of the string are nodes. By changing the position of the end node through frets, the guitarist changes the effective length of the vibrating string and thereby the...
along the string, where the string does not move from its resting position.
Nodes
The nodesNode (physics)
A node is a point along a standing wave where the wave has minimal amplitude. For instance, in a vibrating guitar string, the ends of the string are nodes. By changing the position of the end node through frets, the guitarist changes the effective length of the vibrating string and thereby the...
of natural harmonics are located at the following points along a guitar's neck. Note that for fretted strings, these locations shift up the fingerboard by the same number of frets, and resulting harmonics are called artificial harmonics.
| Mode | Length Fraction | Fret | Note |
|---|---|---|---|
| 1 | 1 | open | unison |
| 2 | 1/2 | 12 | octave |
| 3 | 1/3, 2/3 | 7, 19 | octave + perfect fifth |
| 4 | 1/4, 3/4 | 5, 24 | 2nd octave |
| 5 | 1/5 to 4/5 | 3.9, 8.8, 15.9, 27.9 | 2nd octave + just major third |
| 6 | 1/6, 5/6 | 3.2, 31.0 | 2nd octave + perfect fifth |
| 7 | 1/7 to 6/7 | 2.7, 5.8, 9.7, 14.7, 21.7, 33.7 | 2nd octave + septimal minor seventh |
| 8 | 1/8, 3/8, 5/8, 7/8 | 2.3, 8.1, 17.0, 36.0 | 3rd octave |
| 9 | 1/9, 2/9, 4/9, 5/9, 7/9, 8/9 | 2.0, 4.4, 10.2, 14.0, 26.0, 38.0 | 3rd octave + neutral second |
| 10 | 1/10, 3/10, 7/10, 9/10 | 1.8, 6.2, 20.8, 39.9 | 3rd octave + just major third |
The above fret numbers can be calculated:
where
, the frequency ratio of one musical half-step (i.e. one fret), is the mode number (1-10 are given above), and is the node number for that mode ( to ).Note that 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.
Intervals
| harmonic | stop note | harmonic note | cents | reduced cents |
|---|---|---|---|---|
| 2 | octave Octave In music, an octave is the interval between one musical pitch and another with half or double its frequency. The octave relationship is a natural phenomenon that has been referred to as the "basic miracle of music", the use of which is "common in most musical systems"... |
P8 Octave In music, an octave is the interval between one musical pitch and another with half or double its frequency. The octave relationship is a natural phenomenon that has been referred to as the "basic miracle of music", the use of which is "common in most musical systems"... |
1200.0 | 0.0 |
| 3 | just perfect fifth Perfect fifth In classical music from Western culture, a fifth is a musical interval encompassing five staff positions , and the perfect fifth is a fifth spanning seven semitones, or in meantone, four diatonic semitones and three chromatic semitones... |
P8 + P5 | 1902.0 | 702.0 |
| 4 | just perfect fourth Perfect fourth In classical music from Western culture, a fourth is a musical interval encompassing four staff positions , and the perfect fourth is a fourth spanning five semitones. For example, the ascending interval from C to the next F is a perfect fourth, as the note F lies five semitones above C, and there... |
2P8 | 2400.0 | 0.0 |
| 5 | just major third | 2P8 + just M3 | 2786.3 | 386.3 |
| 6 | just minor third | 2P8 + P5 | 3102.0 | 702.0 |
| 7 | septimal minor third Septimal minor third In music, the septimal minor third , also called the subminor third, is the musical interval exactly or approximately equal to a 7/6 ratio of frequencies. In terms of cents, it is 267 cents, a quartertone of size 36/35 flatter than a just minor third of 6/5... |
2P8 + septimal m7 | 3368.8 | 968.8 |
| 8 | septimal major second Major second In Western music theory, a major second is a musical interval spanning two semitones, and encompassing two adjacent staff positions . For example, the interval from C to D is a major second, as the note D lies two semitones above C, and the two notes are notated on adjacent staff postions... |
3P8 | 3600.0 | 0.0 |
| 9 | Pythagorean major second Major second In Western music theory, a major second is a musical interval spanning two semitones, and encompassing two adjacent staff positions . For example, the interval from C to D is a major second, as the note D lies two semitones above C, and the two notes are notated on adjacent staff postions... |
3P8 + pyth M2 | 3803.9 | 203.9 |
| 10 | just minor whole tone | 3P8 + just M3 | 3986.3 | 386.3 |
| 11 | greater unidecimal neutral second Neutral second A neutral second or medium second is a musical interval wider than a minor second and narrower than a major second. Three distinct intervals may be termed neutral seconds:... |
3P8 + just M3 + GUN2 | 4151.3 | 551.3 |
| 12 | lesser unidecimal neutral second Neutral second A neutral second or medium second is a musical interval wider than a minor second and narrower than a major second. Three distinct intervals may be termed neutral seconds:... |
3P8 + P5 | 4302.0 | 702.0 |
| 13 | tridecimal 2/3-tone | 3P8 + P5 + T23T | 4440.5 | 840.5 |
| 14 | 2/3-tone | 3P8 + P5 + septimal m3 | 4568.8 | 968.8 |
| 15 | septimal (or major) diatonic semitone | 3P8 + P5 + just M3 | 4688.3 | 1088.3 |
| 16 | just (or minor) diatonic semitone | 4P8 | 4800.0 | 0.0 |
Pinch harmonics
- See Pinch harmonicPinch harmonicA pinch harmonic or pick harmonic is a guitar technique in which the player's thumb or index finger on the picking hand slightly catches the string after it is picked, canceling the fundamental of the string, and letting one of the overtones dominate. This results in a high pitched sound...
A pinch harmonic is produced by lightly touching the thumb of the picking hand against the string immediately after it is picked. This action is sufficient to silence the fundamental
Fundamental frequency
The fundamental frequency, often referred to simply as the fundamental and abbreviated f0, is defined as the lowest frequency of a periodic waveform. In terms of a superposition of sinusoids The fundamental frequency, often referred to simply as the fundamental and abbreviated f0, is defined as the...
and all overtone
Overtone
An overtone is any frequency higher than the fundamental frequency of a sound. The fundamental and the overtones together are called partials. Harmonics are partials whose frequencies are whole number multiples of the fundamental These overlapping terms are variously used when discussing the...
s except those that have a nodes
Node (physics)
A node is a point along a standing wave where the wave has minimal amplitude. For instance, in a vibrating guitar string, the ends of the string are nodes. By changing the position of the end node through frets, the guitarist changes the effective length of the vibrating string and thereby the...
at that location. This is generally accomplished by holding the plectrum
Plectrum
A plectrum is a small flat tool used to pluck or strum a stringed instrument. For hand-held instruments such as guitars and mandolins, the plectrum is often called a pick, and is a separate tool held in the player's hand...
so very little of its tip protrudes between the thumb and forefinger (roughly 3–5 mm), allowing the thumb to brush the string immediately after it is picked.
The technique must be performed at one of the appropriate harmonic nodes for the note to sound. For example, to produce a pinch harmonic one octave
Octave
In music, an octave is the interval between one musical pitch and another with half or double its frequency. The octave relationship is a natural phenomenon that has been referred to as the "basic miracle of music", the use of which is "common in most musical systems"...
higher than the fundamental of a string that is stopped at the third fret of a guitar, the string must be plucked halfway between the third fret and the bridge (the 15th fret, as the neck is logarithmic). Other overtones of the same fundamental note may be produced in the same way at other nodes along the string. The point where the string is plucked therefore varies depending on the desired note. Most harmonics have several accessible nodes evenly spaced on the string, so the nodes used in practice are normally around where the string is normally picked (around the pickups on an electric guitar), rather than those above the neck as these are the easiest to access with the picking hand from normal playing.
Overtones with a frequency of a multiple of the intended overtone (i.e., the same note in a higher octave) will share the nodes of the lower overtones, so won't be muted. They will, however, be at a much lower volume and since they are the same note in a higher octave, don't detract from the sound of the note. If the string is pinched at the antinode
Node (physics)
A node is a point along a standing wave where the wave has minimal amplitude. For instance, in a vibrating guitar string, the ends of the string are nodes. By changing the position of the end node through frets, the guitarist changes the effective length of the vibrating string and thereby the...
of the intended overtone, no higher overtones will sound.
A single harmonic overtone is quieter than a normal note, which contains many overtones. For this reason, guitar players often increase the guitar volume to play harmonics. Thicker strings, stronger pickups and adjustment to amplifier settings (increasing gain) are some ways of doing this. Note that when the string vibrates primarily at a single fundamental, it has different volumes through different pickups, depending on the proximity of nodes or antinodes to the pickup. The different overtone volumes are why neck and bridge pickups sound different. If a node is directly over a pickup, little or no sound is heard.
Tapped harmonics
This technique was popularized by Eddie van HalenEddie Van Halen
Edward Lodewijk "Eddie" Van Halen is a Dutch-American guitarist, keyboardist, songwriter and producer, best known as the lead guitarist and co-founder of the hard rock band Van Halen, inducted into the Rock and Roll Hall of Fame...
. Tapped harmonics
Tap harmonic
Tap harmonic is a technique used with fretted string instruments, . It is executed by tapping on the actual fret wire most commonly at the 12th fret, but also can be executed by tapping any of the fret wires with proper technique. It can also be done by gently touching the string over the fret wire...
are an extension of the tapping
Tapping
Tapping is a guitar playing technique, where a string is fretted and set into vibration as part of a single motion of being pushed onto the fretboard, as opposed to the standard technique being fretted with one hand and picked with the other...
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 12+3=15.
String harmonics driven by a magnetic field
This technique is used by effect devices producing a magnetic field that can agitate fundamentalsand harmonics of steel strings. There are harmonic mode switches as provided by newer versions of the
Ebow and by guitar build 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.