In music, timbre (, like tamber, or, from Fr. timbre) is the quality of a musical note or sound or tone that distinguishes different types of sound production, such as voices or musical instruments. The physical characteristics of sound that mediate the perception of timbre include spectrum and envelope. Timbre is also known in psychoacoustics as tone quality or tone color.
For example, timbre is what, with a little practice, people use to distinguish the saxophone from the trumpet in a jazz group, even if both instruments are playing notes at the same pitch and loudness. Timbre has been called a "wastebasket" attribute or category, or "the psychoacoustician's multidimensional wastebasket category for everything that cannot be qualified as pitch or loudness."
Tone quality and color are used as synonyms for timbre. Helmholtz used the German Klangfarbe (tone color), and 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, p.7).
Colors of the optical spectrum are not generally explicitly associated with particular sounds. Rather, the sound of an instrument may be described with words like "bright", "dark", "warm" or "harsh" or other terms. However, color is often used to describe different types of noise such as pink or white.
The American Standards Association defines timbre as "[...] that attribute of sensation in terms of which a listener can judge that two sounds having the same loudness and pitch are dissimilar". A note to the 1960 definition (p.45) adds that "timbre depends primarily upon the spectrum of the stimulus, but it also depends upon the waveform, the sound pressure, the frequency location of the spectrum, and the temporal characteristics of the stimulus ."
J.F. Schouten (1968, p.42) describes the "elusive attributes of timbre" as "determined by at least five major acoustic parameters" which Robert Erickson (1975) finds "scaled to the concerns of much contemporary music":
The richness of a sound or note produced by a musical instrument 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. For example, in western music, instruments are normally tuned to A = 440 Hz. 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 — ×2, ×3, ×4, etc. Partials are other overtones. Most western instruments produce harmonic sounds, but many instruments produce partials and inharmonic tones, such as cymbals and other non-pitched instruments.
When the orchestral tuning note is played, the sound is a combination of 440 Hz, 880 Hz, 1320 Hz, 1760 Hz and so on. The balance of the amplitudes of the different frequencies is responsible for the characteristic sound of each instrument.
The fundamental is not necessarily the strongest component of the overall sound. But it is implied by the existence of the harmonic series — the A above would be distinguishable from the one an octave below (220 Hz, 440 Hz, 660 Hz, 880 Hz) by the presence of the third harmonic, even if the fundamental were indistinct. Similarly, a pitch is often inferred from non-harmonic spectra, supposedly through a mapping process, an attempt to find the closest harmonic fit.
It is possible to add artificial 'subharmonics' to the sound using electronic effects but, again, this does not affect the naming of the note.
William Sethares (2004) wrote that just intonation and the western equal tempered scale derive from the harmonic spectra/timbre of most western instruments. Similarly the specific inharmonic timbre of Thai metallophones would produce the seven-tone near-equal temperament they do indeed employ. The five-note sometimes near-equal tempered slendro scale provides the most consonance in the combination of the inharmonic spectra of Balinese metallophones with harmonic instruments such as the stringed rebab.
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 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 blat of the player's lips 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.
Timbre is often cited as one of the fundamental aspects of music. Formally, timbre and other factors are usually secondary to pitch. "To a marked degree the music of Debussy elevates timbre to an unprecedented structural status; already in L'Apres-midi d'un Faune the color of flute and harp functions referentially," according to Jim Samson (1977). Surpassing Debussy is Klangfarbenmelodie and surpassing that the use of sound masses.
Erickson (ibid, p.6) gives a table of subjective experiences and related physical phenomena based on Schouten's five attributes:
|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)|
|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|
Often listeners are able to identify the kind of instrument even across "conditions of changing pitch and loudness, in different environments and with different players." In the case of the clarinet, an acoustic analysis of the waveforms shows they are irregular enough to suggest three instruments rather than one. David Luce (1963, p.17) suggests that this implies "certain 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 the borrowing from studies of vision and visual perception the concept of subjective constancy. (Erickson 1975, p.11)