Guitar Harmonics: Touch, Don't Press
Barely touch a guitar string over the twelfth fret, pluck it, and a bell rings out. Natural harmonics are played by touching the string, not pressing it, right over certain frets. See why it works: a vibrating string hides a whole series of harmonics, and touching it at a half, a third, a quarter or a fifth of its length (12th, 7th, 5th fret and near the 4th) leaves only the 2nd, 3rd, 4th or 5th harmonic ringing, because the light touch makes a still point, a node. On the low E string that series is E, E, B, E, G sharp: an E major chord hidden in one string. Then tune by ear with harmonics, listening for beats, and play the series on the piano. Every guitar sound is our own synthetic demonstration. The last lesson of Voice and Guitar, with a look back at the whole module.
In this lesson you'll
- Find the natural harmonics of a guitar string: 12th fret (half: 2nd harmonic, one octave up), 7th fret (a third: 3rd harmonic, an octave and a fifth up), 5th fret (a quarter: 4th harmonic, two octaves up) and near the 4th fret (a fifth: 5th harmonic, two octaves and a major third up).
- Explain why a light touch works: the string vibrates in 2, 3, 4 or 5 segments, and the touch makes a node that kills every vibration that would need to move there; spell the low E string's series (E2, E3, B3, E4, G sharp 4), the same harmonic series as in lessons 50 and 83.
- Tune with harmonics: match the 5th-fret harmonic of one string to the 7th-fret harmonic of the next until the beats stop (lesson 49), know why it fails between G and B (the major third of lesson 86), and tell a pressed note from a bell-like harmonic by ear.
Remember
Guitarists play natural harmonics by touching the string lightly right over certain frets, without pressing it, then plucking: pressing gives a plain note, touching gives a bell-like tone.
Touch at 1/2, 1/3, 1/4 or 1/5 of the string and it vibrates in 2, 3, 4 or 5 segments: the 2nd, 3rd, 4th or 5th harmonic (octave, octave and a fifth, two octaves, two octaves and a major third). The light touch makes a node and kills the vibrations that would need to move there.
The 5th-fret harmonic of one string should match the 7th-fret harmonic of the next: if they differ you hear beats, and when the beating stops you are in tune. It works for every neighbouring pair except G and B.