Harmonic

A harmonic is a special kind of wave that connects to another wave called the fundamental frequency. Imagine a wave that repeats, like a pendulum swinging or a guitar string vibrating. You can also create other waves that vibrate at exact multiples of the original speed. These are called harmonics.

For example, if the fundamental frequency is 50 Hz, a common speed for electricity in power lines, the next harmonics might vibrate at 100 Hz, 150 Hz, and so on.

Harmonics are important in many areas, such as music, physics, and communications. In music, harmonics help musicians create beautiful, high notes and special sounds on instruments like violins and flutes. When a player gently touches a string at the right spot, the string can vibrate in smaller sections, making a clear, "glassy" tone different from normal notes.

In physics and technology, harmonics help explain how different waves behave, especially in sound and electrical systems. This knowledge helps scientists and engineers design better instruments, reduce unwanted noise, and improve how we send information through radio waves.

Terminology

In music and sound, harmonics are sometimes called "overtones" or "partials." These words are similar, but they mean a little different things. A "harmonic" includes all the notes in a special series of sounds, including the main note, called the fundamental frequency. An "overtone" only means the notes that are higher than the main note.

Characteristics

Most musical instruments make sounds from many small, simple tones mixed together. Our ears hear these mixed tones as one note. What makes a note sound unique — like a piano versus a flute — depends on how strong each small tone is.

Instruments like violins or flutes create tones that fit together neatly. These tones match exact multiples of a main tone, called the fundamental frequency. These are called harmonics. But not all instruments work this way. For example, cymbals and drums create tones that don’t fit this pattern and don’t sound like a clear note. Instruments like pianos mix both kinds of tones, which helps them sound rich and full.

Main article: timbre
Main articles: oscillators, human voice
Further information: resonators, transverse flute, trumpets, clarinets, non-linearly, elastic, gut, brass or steel strings, inharmonic partials, pianos, pizzicato, singing bowls, multiphonics, cymbals, Sethares, dynamic tonality, consonance

Partials, overtones, and harmonics

An overtone is a note that sounds higher than the lowest note in a combined sound. These notes give each musical instrument its special sound, or timbre.

In instruments like strings and winds, these higher notes are often called harmonics. They are also known as partials.

Many instruments can play higher notes without first playing the main note. For example, a recorder can play a note an octave higher by a method called overblowing. String instruments can make very clear, high notes called harmonics or flageolets. These notes are often used to check if the strings are in tune. Not all instruments follow this exact pattern. Instruments like xylophones and drums can make notes that don’t fit neatly into a harmonic series.

On stringed instruments

Main article: String harmonic

Harmonics are special notes you can play on stringed instruments like violins. There are two ways to play them. First, you can move the bow closer to the bridge of the instrument. Second, you can gently touch certain points, or nodes, along an open string with your finger. These points divide the string into equal parts, like halves, thirds, or quarters.

When musicians play harmonics, the sound is delicate and flute-like. This can add beautiful color to music. It is rare to play harmonics higher than the fifth note on most string instruments. But larger instruments like the double bass can make more harmonics because of their longer strings.

Artificial harmonics

Sometimes musicians need to play a special note called an artificial harmonic. They do this by pressing one finger to make the string shorter. Then they use another finger to touch a node for the harmonic note they want.

Other information

Harmonics can be used in music and sound systems. Composer Arnold Dreyblatt plays harmonics on a special double bass using a unique bowing technique. Another composer, Lawrence Ball, uses harmonics to make music with electronic tools.