In music, timbre (pronounced "tahm-ber" or "tihm-ber") is the way a musical note, sound, or tone sounds to the ear. Timbre helps people tell sounds apart based on their source, such as the voices of a choir or the sounds of different musical instruments. It also allows listeners to recognize different instruments within the same group, like an oboe and a clarinet, which are both woodwind instruments.

In simple terms, timbre is what makes one musical instrument or voice sound different from another, even when they play or sing the same note. For example, a guitar and a piano can sound the same when playing the same note at the same loudness. However, each instrument still has its own unique sound. Musicians can tell instruments apart based on their different timbres, even if the instruments play the same pitch and volume.

The physical traits that affect timbre include the frequency spectrum (the range of sound frequencies) and the envelope (how the sound starts, changes, and ends).

Musicians can change timbre by adjusting how they sing or play. For example, a violinist can use different bowing styles or play on different parts of the string. Playing near the fingerboard produces a soft, airy sound, while playing near the bridge creates a rough, intense sound. On electric guitars and pianos, performers can change timbre using tools like effects units and graphic equalizers.

Synonyms

Tone quality and tone color are other names for timbre, which describes how a single instrument sounds. The word "texture" can also mean how music is arranged, such as many melodies played together or one main melody with supporting chords. Hermann von Helmholtz used the German word Klangfarbe (tone color), and John Tyndall suggested the English term clangtint. However, Alexander Ellis did not approve of these terms because they already had different meanings in English. The sound of a musical instrument depends on its frequency composition and can be described using words like bright, dark, warm, or harsh. There are also types of noise with names like pink and white. In visual representations of sound, timbre is shown by the shape of the image, loudness is shown by brightness, and pitch is shown by the vertical position on a spectrogram.

ASA definition

The Acoustical Society of America (ASA) defines timbre in its Acoustical Terminology (definition 12.09) as "the quality of sound that allows a listener to recognize that two sounds, which are not the same, have different characteristics even if they are presented in the same way, have the same loudness, and the same pitch." The definition also explains that timbre is mainly influenced by the pattern of sound waves (frequency spectrum), but it is also affected by how strong the sound waves are (sound pressure) and how the sound changes over time (temporal characteristics).

Attributes

Many experts have broken down timbre into smaller parts. For example, Schouten described the "hard-to-describe qualities of timbre" as being influenced by at least five major sound-related factors. Robert Erickson found these factors to be important in much contemporary music:

• The balance between a sound that has a clear pitch and one that sounds more like noise
• The shape of the sound’s frequency pattern (spectral envelope)
• The way a sound changes over time, including how quickly it starts (attack), how long it lasts (duration), and how it fades (decay) (ADSR, which stands for "attack, decay, sustain, release")
• Changes in the frequency pattern (formant-glide) and the main pitch (micro-intonation)
• The beginning of a sound (prefix or onset), which may be very different from the rest of the sound

A tonal sound is one with a clear pitch, like pressing a piano key. A noiselike sound is one that lacks a clear pitch, such as white noise.

Erickson created a table that connects how people describe sounds (subjective experiences) to the physical properties of sound based on these factors.

The richness of a sound from a musical instrument is sometimes described as the combination of many different frequencies. The lowest frequency is called the fundamental frequency, and the pitch it creates is used to name the note. However, the fundamental frequency is not always the loudest. The loudest frequency is always a multiple of the fundamental frequency. For example, the loudest frequency in a transverse flute is twice the fundamental frequency. Other important frequencies are called overtones, which may include harmonics and partials. Harmonics are frequencies that are whole-number multiples of the fundamental frequency, such as 2×, 3×, 4×, etc. Partials are other overtones. Sometimes, frequencies that are smaller than the fundamental frequency (subharmonics) also occur. Most instruments produce harmonic sounds, but some, like cymbals and other instruments that do not have a clear pitch, produce partials and inharmonic tones.

When an orchestra or concert band plays a tuning note, the sound includes frequencies like 440 Hz, 880 Hz, 1320 Hz, 1760 Hz, and so on. Each instrument in the group creates a unique mix of these frequencies, along with harmonics and overtones. These sound waves overlap and combine, and the balance of their loudness (amplitudes) helps create the unique sound of each instrument.

William Sethares wrote that just intonation and the Western equal-tempered scale are connected to the harmonic patterns of many Western instruments in a way similar to how the inharmonic sound of the Thai renat (a xylophone-like instrument) is linked to the seven-tone near-equal tempered pelog scale used in its music. Similarly, the inharmonic sounds of Balinese metallophones, when played with harmonic instruments like the rebab (a stringed instrument) or the human voice, are connected to the five-note near-equal tempered slendro scale used in Indonesian gamelan music.

The timbre of a sound is also influenced by the shape of its envelope, which includes how quickly the sound starts (attack time), how it fades (decay), how long it stays loud (sustain), and how it ends (release) (ADSR envelope). These are common features on professional synthesizers. For example, if the attack of a piano or trumpet sound is removed, it becomes harder to recognize the instrument, because the initial sound of the hammer hitting the strings or the player’s lips hitting the trumpet mouthpiece is a key part of how we identify these instruments. The envelope describes the overall loudness pattern of a sound.

In music history

During the eighteenth and nineteenth centuries, the sound of instruments, called timbre, became more important in how music was arranged for orchestras. Composers like Berlioz and Wagner helped make timbre a key part of orchestral music in the nineteenth century. For example, in Wagner's opera Die Walküre, the "Sleep motif" from Act 3 uses a series of notes that go down step by step, called a chromatic scale. This scale is played by different groups of instruments: first the flute and oboe in the woodwinds, then the strings with violins leading, and finally the brass section with French horns.

Debussy, who wrote music in the late nineteenth and early twentieth centuries, is known for making timbre even more important in music. In his piece Prélude à l'après-midi d'un faune, the sounds of the flute and harp are used to represent ideas or images. Mahler, a composer from the early twentieth century, also showed how different instrument sounds were used in his music. In the Scherzo movement of his Sixth Symphony, Norman Del Mar describes how Mahler moves a repeated note through many different instrument sounds, such as horns and plucked strings, then trumpet, clarinet, flute, piccolo, and finally oboe.

In rock music from the late 1960s to the 2000s, the unique sound of specific instruments is important. For example, in heavy metal music, the loud and distorted sound of power chords played on electric guitars through large amplifiers and speaker setups is a key part of the music's style. This sound is a major part of what makes the genre recognizable. (See also Klangfarbenmelodie.)

Psychoacoustic evidence

Listeners can often recognize an instrument even when it is played at different pitches, volumes, in various settings, or by different musicians. For the clarinet, studies of sound show waveforms that are so different they appear to be from three separate instruments instead of one. David Luce suggests this may mean that

However, Robert Erickson argues that there are few consistent patterns that explain how people can still recognize and identify instruments. He proposes using the idea of "subjective constancy" from vision research, which describes how people see objects as the same even when lighting or angles change.

Experiments in psychoacoustics since the 1960s have aimed to explain how timbre works. One method involves playing pairs of sounds to listeners and then using a mathematical tool called multidimensional scaling to combine their judgments about how different the sounds seem. The most common results from these experiments show that two factors are especially important: brightness, or how sound energy is spread across different frequencies, and "bite," which refers to how quickly and in sync the sound starts.

Tristimulus timbre model

The idea of tristimulus comes from the study of color, where it explains how three main colors can be combined to make any other color. In music, tristimulus refers to how different sound parts, called harmonics, are grouped into three sections to describe a sound. This method simplifies a large number of sound parts—sometimes dozens or hundreds—into just three values. The first value shows how strong the first harmonic is. The second value shows how strong the second, third, and fourth harmonics are together. The third value shows how strong all the other harmonics are combined. More research and studies are needed to determine if this method is effective.

Brightness

The word "brightness" is also used when talking about how sounds feel to the ear, similar to how we describe brightness in vision. Scientists who study sound timbre believe brightness is one of the most noticeable ways sounds differ. They describe it using sound science, focusing on how much high-pitched sound is present, and they use a measure called the spectral centroid to help explain this.