# Timbre

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In music, timbre ( TAM-bər, TIM-, French: ), also known as tone color or tone quality (from psychoacoustics), is the perceived sound quality of a musical note, sound or tone. Timbre distinguishes different types of sound production, such as choir voices and musical instruments, such as string instruments, wind instruments, and percussion instruments. It also enables listeners to distinguish different instruments in the same category (e.g., an oboe and a clarinet, both woodwind instruments).

Psychoacoustics is the scientific study of sound perception and audiology—how humans perceive various sounds. More specifically, it is the branch of science studying the psychological and physiological responses associated with sound. It can be further categorized as a branch of psychophysics. Psychoacoustics received its name from a field within psychology—i.e., recognition science—which deals with all kinds of human perceptions. It is an interdisciplinary field of many areas, including psychology, acoustics, electronic engineering, physics, biology, physiology, and computer science.

In music, a note is a symbol denoting a musical sound. In English usage a note is also the sound itself.

## Contents

The physical characteristics of sound that determine the perception of timbre include spectrum and envelope. Singers and instrumental musicians can change the timbre of the music they are singing/playing by using different singing or playing techniques. For example, a violinist can use different bowing styles or play on different parts of the string to obtain different timbres (e.g., playing sul tasto produces a light, airy timbre, whereas playing sul ponticello produces a harsh, even and aggressive tone). On electric guitar and electric piano, performers can change the timbre using effects units and graphic equalizers.

A spectrum is a condition that is not limited to a specific set of values but can vary, without steps, across a continuum. The word was first used scientifically in optics to describe the rainbow of colors in visible light after passing through a prism. As scientific understanding of light advanced, it came to apply to the entire electromagnetic spectrum.

In sound and music, an envelope describes how a sound changes over time. It normally relates to the amplitude (volume), but it may also involve elements such as filters (frequencies) or pitch. For example, a piano key, when struck and held, creates a near-immediate initial sound which gradually decreases in volume to zero. Envelope generators, which allow users to control the different stages of a sound, are common features of synthesizers, samplers, and other electronic musical instruments.

An effects unit or effectspedal is an electronic or digital device that alters the sound of a musical instrument or other audio source. Common effects include distortion/overdrive, often used with electric guitar in electric blues and rock music; dynamic effects such as volume pedals and compressors, which affect loudness; filters such as wah-wah pedals and graphic equalizers, which modify frequency ranges; modulation effects, such as chorus, flangers and phasers; pitch effects such as pitch shifters; and time effects, such as reverb and delay, which create echoing sounds and emulate the sound of different spaces.

In simple terms, timbre is what makes a particular musical sound have a different sound from another. For instance, it is the difference in sound between a guitar and a piano playing the same note at the same volume. Both instruments can sound equally tuned in relation to each other as they play the same note, and while playing at the same amplitude level each instrument will still sound distinctively with its own unique tone color. Experienced musicians are able to distinguish between different instruments of the same type based on their varied timbres, even if those instruments are playing notes at the same fundamental pitch and loudness.

Pitch is a perceptual property of sounds that allows their ordering on a frequency-related scale, or more commonly, pitch is the quality that makes it possible to judge sounds as "higher" and "lower" in the sense associated with musical melodies. Pitch can be determined only in sounds that have a frequency that is clear and stable enough to distinguish from noise. Pitch is a major auditory attribute of musical tones, along with duration, loudness, and timbre.

## Synonyms

Tone quality and tone color are synonyms for timbre, as well as the "texture attributed to a single instrument". However, the word texture can also refer to the type of music, such as multiple, interweaving melody lines versus a singable melody accompanied by subordinate chords. Hermann von Helmholtz used the German Klangfarbe (tone color), and John Tyndall proposed an English translation, clangtint, but both terms were disapproved of by Alexander Ellis, who also discredits register and color for their pre-existing English meanings ( Erickson 1975 , 7). The sound of a musical instrument may be described with words such as bright, dark, warm, harsh, and other terms. There are also colors of noise, such as pink and white. In visual representations of sound, timbre corresponds to the shape of the image ( Abbado 1988 , 3), while loudness corresponds to brightness; pitch corresponds to the y-shift of the spectrogram.

In music, polyphony is one type of musical texture, where a texture is, generally speaking, the way that melodic, rhythmic, and harmonic aspects of a musical composition are combined to shape the overall sound and quality of the work. In particular, polyphony consists of two or more simultaneous lines of independent melody, as opposed to a musical texture with just one voice, monophony, or a texture with one dominant melodic voice accompanied by chords, which is called homophony.

In music, homophony is a texture in which a primary part is supported by one or more additional strands that flesh out the harmony and often provide rhythmic contrast. This differentiation of roles contrasts with equal-voice polyphony and monophony. Historically, homophony and its differentiated roles for parts emerged in tandem with tonality, which gave distinct harmonic functions to the soprano, bass and inner voices.

Hermann Ludwig Ferdinand von Helmholtz was a German physician and physicist who made significant contributions in several scientific fields. The largest German association of research institutions, the Helmholtz Association, is named after him.

## ASA definition

The Acoustical Society of America (ASA) Acoustical Terminology definition 12.09 of timbre describes it as "that attribute of auditory sensation which enables a listener to judge that two nonidentical sounds, similarly presented and having the same loudness and pitch, are dissimilar", adding, "Timbre depends primarily upon the frequency spectrum, although it also depends upon the sound pressure and the temporal characteristics of the sound" ( Acoustical Society of America Standards Secretariat 1994 ).

## Attributes

Timbre has been called "...the psychoacoustician's multidimensional waste-basket category for everything that cannot be labeled pitch or loudness." (McAdams and Bregman 1979 , 34; cf. Dixon Ward 1965 , 55 and Tobias 1970 , 409).

Many commentators have attempted to decompose timbre into component attributes. For example, J. F. Schouten (1968, 42) describes the "elusive attributes of timbre" as "determined by at least five major acoustic parameters", which Robert Erickson (1975 , 5) finds, "scaled to the concerns of much contemporary music":

1. Range between tonal and noiselike character
2. Spectral envelope
3. Time envelope in terms of rise, duration, and decay (ADSR, which stands for "attack, decay, sustain, release")
4. Changes both of spectral envelope (formant-glide) and fundamental frequency (micro-intonation)
5. Prefix, or onset of a sound, quite dissimilar to the ensuing lasting vibration

An example of a tonal sound is a musical sound that has a definite pitch, such as pressing a key on a piano; a sound with a noiselike character would be white noise, the sound similar to that produced when a radio is not tuned to a station.

Erickson (1975 , 6) gives a table of subjective experiences and related physical phenomena based on Schouten's five attributes:

 Subjective Objective Tonal character, usually pitched Periodic sound Noisy, with or without some tonal character, including rustle noise Noise, including random pulses characterized by the rustle time (the mean interval between pulses) Coloration Spectral envelope Beginning/ending Physical rise and decay time Coloration glide or formant glide Change of spectral envelope Microintonation Small change (one up and down) in frequency Vibrato Frequency modulation Tremolo Amplitude modulation Attack Prefix Final sound Suffix

### Harmonics

The richness of a sound or note a musical instrument produces is sometimes described in terms of a sum of a number of distinct frequencies. The lowest frequency is called the fundamental frequency , and the pitch it produces is used to name the note, but the fundamental frequency is not always the dominant frequency. The dominant frequency is the frequency that is most heard, and it is always a multiple of the fundamental frequency. For example, the dominant frequency for the transverse flute is double the fundamental frequency. Other significant frequencies are called overtones of the fundamental frequency, which may include harmonics and partials. Harmonics are whole number multiples of the fundamental frequency, such as ×2, ×3, ×4, etc. Partials are other overtones. There are also sometimes subharmonics at whole number divisions of the fundamental frequency. Most instruments produce harmonic sounds, but many instruments produce partials and inharmonic tones, such as cymbals and other indefinite-pitched instruments.

When the tuning note in an orchestra or concert band is played, the sound is a combination of 440 Hz, 880 Hz, 1320 Hz, 1760 Hz and so on. Each instrument in the orchestra or concert band produces a different combination of these frequencies, as well as harmonics and overtones. The sound waves of the different frequencies overlap and combine, and the balance of these amplitudes is a major factor in the characteristic sound of each instrument.

William Sethares wrote that just intonation and the western equal tempered scale are related to the harmonic spectra/timbre of many western instruments in an analogous way that the inharmonic timbre of the Thai renat (a xylophone-like instrument) is related to the seven-tone near-equal tempered pelog scale in which they are tuned. Similarly, the inharmonic spectra of Balinese metallophones combined with harmonic instruments such as the stringed rebab or the voice, are related to the five-note near-equal tempered slendro scale commonly found in Indonesian gamelan music ( Sethares 1998 , 6, 211, 318).

### Envelope

The timbre of a sound is also greatly affected by the following aspects of its envelope: attack time and characteristics, decay, sustain, release (ADSR envelope) and transients. Thus these are all common controls on professional synthesizers. For instance, if one takes away the attack from the sound of a piano or trumpet, it becomes more difficult to identify the sound correctly, since the sound of the hammer hitting the strings or the first blast of the player's lips on the trumpet mouthpiece are highly characteristic of those instruments. The envelope is the overall amplitude structure of a sound, so called because the sound just "fits" inside its envelope: what this means should be clear from a time-domain display of almost any interesting sound, zoomed out enough that the entire waveform is visible.

## In music history

Instrumental timbre played an increasing role in the practice of orchestration during the eighteenth and nineteenth centuries. Berlioz ( Macdonald 1969 , 51) and Wagner ( Latham ) made significant contributions to its development during the nineteenth century. For example, Wagner’s “Sleep motif” from Act 3 of his opera Die Walküre , features a descending chromatic scale that passes through a gamut of orchestral timbres. First the woodwind (flute, followed by oboe), then the massed sound of strings with the violins carrying the melody, and finally the brass (French horns).

Debussy, who composed during the last decades of the nineteenth and the first decades of the twentieth centuries, has been credited with elevating further the role of timbre: "To a marked degree the music of Debussy elevates timbre to an unprecedented structural status; already in Prélude à l'après-midi d'un faune the color of flute and harp functions referentially" ( Samson 1977 , p. 195). Mahler’s approach to orchestration illustrates the increasing role of differentiated timbres in music of the early twentieth century. Norman Del Mar (1980 , 48) describes the following passage from the Scherzo movement of his Sixth Symphony, as "a seven-bar link to the trio consisting of an extension in diminuendo of the repeated As… though now rising in a succession of piled octaves which moreover leap-frog with Cs added to the As. The lower octaves then drop away and only the Cs remain so as to dovetail with the first oboe phrase of the trio." During these bars, Mahler passes the repeated notes through a gamut of instrumental colors, mixed and single: starting with horns and pizzicato strings, progressing through trumpet, clarinet, flute, piccolo and finally, oboe:

In rock music from the late 1960s to the 2000s, the timbre of specific sounds is important to a song. For example, in heavy metal music, the sonic impact of the heavily amplified, heavily distorted power chord played on electric guitar through very loud guitar amplifiers and rows of speaker cabinets is an essential part of the style's musical identity. You could not take the heavily amplified electric guitar part and substitute it with the same notes played on a grand piano or pipe organ.[ citation needed ]

## Psychoacoustic evidence

Often, listeners can identify an instrument, even at different pitches and loudness, in different environments, and with different players. In the case of the clarinet, acoustic analysis shows waveforms irregular enough to suggest three instruments rather than one. David Luce (1963 , 16) suggests that this implies that "[C]ertain strong regularities in the acoustic waveform of the above instruments must exist which are invariant with respect to the above variables." However, Robert Erickson argues that there are few regularities and they do not explain our "...powers of recognition and identification." He suggests borrowing the concept of subjective constancy from studies of vision and visual perception ( Erickson 1975 , 11).

Psychoacoustic experiments from the 1960s onwards tried to elucidate the nature of timbre. One method involves playing pairs of sounds to listeners, then using a multidimensional scaling algorithm to aggregate their dissimilarity judgments into a timbre space. The most consistent outcomes from such experiments are that brightness or spectral energy distribution ( Grey 1977 ), and the bite, or rate and synchronicity ( Wessel 1979 ) and rise time ( Lakatos 2000 ), of the attack are important factors.

## Tristimulus timbre model

The concept of tristimulus originates in the world of color, describing the way three primary colors can be mixed together to create a given color. By analogy, the musical tristimulus measures the mixture of harmonics in a given sound, grouped into three sections. It is basically a proposal of reducing a huge number of sound partials, that can amount to dozens or hundreds in some cases, down to only three values. The first tristimulus measures the relative weight of the first harmonic; the second tristimulus measures the relative weight of the second, third, and fourth harmonics taken together; and the third tristimulus measures the relative weight of all the remaining harmonics (Peeters 2003; Pollard and Jansson 1982, [ page needed ]): More evidences, studies and applications would be needed regarding this type of representation, in order to validate it.

${\displaystyle T_{1}={\frac {a_{1}}{\sum _{h=1}^{H}{a_{h}}}}\qquad T_{2}={\frac {a_{2}+a_{3}+a_{4}}{\sum _{h=1}^{H}{a_{h}}}}\qquad T_{3}={\frac {\sum _{h=5}^{H}{a_{h}}}{\sum _{h=1}^{H}{a_{h}}}}}$

## Brightness

The term "brightness" is also used in discussions of sound timbres, in a rough analogy with visual brightness. Timbre researchers consider brightness to be one of the perceptually strongest distinctions between sounds, [1] and formalize it acoustically as an indication of the amount of high-frequency content in a sound, using a measure such as the spectral centroid.

## Related Research Articles

A harmonic series is the sequence of sounds—pure tones, represented by sinusoidal waves—in which the frequency of each sound is an integer multiple of the fundamental, the lowest frequency.

In music, there are two common meanings for tuning:

A harmonic is any member of the harmonic series. The term is employed in various disciplines, including music, physics, acoustics, electronic power transmission, radio technology, and other fields. It is typically applied to repeating signals, such as sinusoidal waves. A harmonic of such a wave is a wave with a frequency that is a positive integer multiple of the frequency of the original wave, known as the fundamental frequency. The original wave is also called the 1st harmonic, the following harmonics are known as higher harmonics. As all harmonics are periodic at the fundamental frequency, the sum of harmonics is also periodic at that frequency. For example, if the fundamental frequency is 50 Hz, a common AC power supply frequency, the frequencies of the first three higher harmonics are 100 Hz, 150 Hz, 200 Hz and any addition of waves with these frequencies is periodic at 50 Hz.

An nth characteristic mode, for n > 1, will have nodes that are not vibrating. For example, the 3rd characteristic mode will have nodes at L and L, where L is the length of the string. In fact, each nth characteristic mode, for n not a multiple of 3, will not have nodes at these points. These other characteristic modes will be vibrating at the positions L and L. If the player gently touches one of these positions, then these other characteristic modes will be suppressed. The tonal harmonics from these other characteristic modes will then also be suppressed. Consequently, the tonal harmonics from the nth characteristic modes, where n is a multiple of 3, will be made relatively more prominent.

An overtone is any frequency greater than the fundamental frequency of a sound. Using the model of Fourier analysis, the fundamental and the overtones together are called partials. Harmonics, or more precisely, harmonic partials, are partials whose frequencies are numerical integer multiples of the fundamental. These overlapping terms are variously used when discussing the acoustic behavior of musical instruments. The model of Fourier analysis provides for the inclusion of inharmonic partials, which are partials whose frequencies are not whole-number ratios of the fundamental.

In music, inharmonicity is the degree to which the frequencies of overtones depart from whole multiples of the fundamental frequency.

A harmonic sound is said to have a missing fundamental, suppressed fundamental, or phantom fundamental when its overtones suggest a fundamental frequency but the sound lacks a component at the fundamental frequency itself. The brain perceives the pitch of a tone not only by its fundamental frequency, but also by the periodicity implied by the relationship between the higher harmonics; we may perceive the same pitch even if the fundamental frequency is missing from a tone.

Piano acoustics are the physical properties of the piano that affect its sound.

Musical acoustics or music acoustics is a branch of acoustics concerned with researching and describing the physics of music – how sounds are employed to make music. Examples of areas of study are the function of musical instruments, the human voice, computer analysis of melody, and in the clinical use of music in music therapy.

In music, consonance and dissonance are categorizations of simultaneous or successive sounds. Consonance is associated with sweetness, pleasantness, and acceptability; dissonance is associated with harshness, unpleasantness, or unacceptability.

Stretched tuning is a detail of musical tuning, applied to wire-stringed musical instruments, older, non-digital electric pianos, and some sample-based synthesizers based on these instruments, to accommodate the natural inharmonicity of their vibrating elements. In stretched tuning, two notes an octave apart, whose fundamental frequencies theoretically have an exact 2:1 ratio, are tuned slightly farther apart. "For a stretched tuning the octave is greater than a factor of 2; for a compressed tuning the octave is smaller than a factor of 2."

In music, the undertone series or subharmonic series is a sequence of notes that results from inverting the intervals of the overtone series. While overtones naturally occur with the physical production of music on instruments, undertones must be produced in unusual ways. While the overtone series is based upon arithmetic multiplication of frequencies, resulting in a harmonic series, the undertone series is based on arithmetic division.

Harshness, in music information retrieval, is a Non-Contextual Low-Level Audio Descriptors (NLDs) that represents one dimension of the multi-dimensional psychoacoustic feature called as musical timbre.

Virtual pitch is a pitch at the missing fundamental of a harmonic complex tone. It corresponds to the phenomenon whereby one's brain extracts tones from everyday signals and music, even if parts of the signal are masked by other sounds. Virtual pitch is contrasted to spectral pitch, which is the pitch of a pure tone or spectral component. Virtual pitch is called "virtual" because there is no acoustical correlate at the frequency corresponding to the pitch: even when a virtual pitch corresponds to a physically present fundamental, as it often does in everyday harmonic complex tones, the exact virtual pitch depends on the exact frequencies of higher harmonics and is almost independent of the exact frequency of the fundamental.

Dynamic tonality is tonal music which uses real-time changes in tuning and timbre to perform new musical effects such as polyphonic tuning bends, new chord progressions, and temperament modulations, with the option of consonance. The performance of dynamic tonality requires an isomorphic keyboard driving a music synthesizer which implements dynamic tuning and dynamic timbres. Dynamic tonality was discovered by Andrew Milne, William Sethares, and Jim Plamondon.

In physics, sound is a vibration that typically propagates as an audible wave of pressure, through a transmission medium such as a gas, liquid or solid.

William A. Sethares is an American music theorist and professor of electrical engineering at the University of Wisconsin. In music, he has contributed to the theory of Dynamic Tonality and provided a formalization of consonance.

Traditionally in Western music, a musical tone is a steady periodic sound. A musical tone is characterized by its duration, pitch, intensity, and timbre. The notes used in music can be more complex than musical tones, as they may include aperiodic aspects, such as attack transients, vibrato, and envelope modulation.

An unpitched percussion instrument is a percussion instrument played in such a way as to produce sounds of indeterminate pitch, or an instrument normally played in this fashion.

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