Have you ever wondered about the mesmerizing sounds that guitarists create? Those enchanting tones are produced through the art of harmonics. Harmonics are those beautiful hidden notes that resonate alongside the fundamental frequency when a guitar string is plucked. In this article, we will explore the various techniques of playing harmonics and dive into the physics behind their magical properties.
Open-string harmonics, also known as natural harmonics, are the easiest to produce. By lightly touching the strings at specific points without pressing them down, you can unleash the harmonic tones. Each point produces a different note, and the diagram below illustrates the locations where these harmonics can be found.
Playing fretted harmonics requires a bit more skill and precision. It involves fretting a note and delicately touching the string exactly 12 frets above the fretted note. Additionally, the string must be plucked to activate the harmonic. To achieve this, a technique involving the combination of a soft touch and plucking is employed. There are two commonly used techniques for fretted harmonics: artificial harmonics and pinched harmonics.
Technique 1: Artificial Harmonics
Artificial harmonics are the most commonly used technique for playing fretted harmonics. It involves softly touching the string with the index finger and then plucking it with either the pinky finger or a pick held in the other fingers. This technique produces a distinctive sound that many guitarists love.
Technique 2: Pinched Harmonics
Mastering pinched harmonics can be challenging, but it allows for faster execution of fretted harmonics once mastered. This technique requires a modified picking technique along with a steady and accurate picking hand. The pick is held in such a way that it barely clears the bottom of the thumb, allowing for simultaneous plucking and thumb contact to produce the harmonic. The “sweet spot” for plucking the string depends on where the thumb produces the harmonic, which is approximately halfway between the bridge and the fret being played. It’s worth noting that hitting different “sweet spots” on the string will produce different notes, adding to the complexity and versatility of pinched harmonics.
The Physics of Harmonics
To understand why harmonics are produced, we need to delve into the physics of vibrating guitar strings. When you touch the string at certain points, you modify the way the string vibrates. Open-string harmonics split the string into halves, thirds, fourths, fifths, and sixths. Playing harmonics at the 12th fret splits the string in half, while harmonics at the 7th or 19th fret split the string into thirds, and so on. Interestingly, harmonics at the 7th and 19th frets produce the exact same notes, demonstrating the mathematical relationships at play.
The phenomenon occurs because the finger acts as a pivot point for the string, forcing it to vibrate in specific fractions. These fractions determine the wavelength, which in turn determines the frequency and ultimately the note produced. For example, tuning the first string to an A at 440 Hz means that the wavelength is halved compared to the open string, resulting in a higher pitch A note.
Furthermore, differences in string tension and diameter also contribute to the variation in sound across strings of the same length. Adjusting the tension alters the way the string vibrates, leading to different frequencies and tones. The tension changes the diameter of the string, with stretching or tightening making the diameter smaller.
In conclusion, harmonics add depth and complexity to guitar playing, captivating audiences with their ethereal sounds. By mastering the techniques of playing harmonics and understanding the physics behind them, guitarists can unlock a world of creative possibilities and create truly mesmerizing music.