timbre

Timbre, also called tone color, is the quality of a sound that distinguishes two sounds with the same pitch and loudness. It arises from the sound’s spectral content and its time evolution, including the relative strengths of partials (harmonics and overtones) and the shape of the amplitude envelope.

In almost all musical sounds, a fundamental frequency is accompanied by higher partials. The specific amplitudes, phases, and distribution of these components create a characteristic timbre. The spectral envelope, or how energy is spread across frequencies, strongly influences perceived brightness or darkness of the sound. Temporal aspects, such as how quickly a sound arrives (attack) and dissipates (decay, sustain, release), also shape timbre, particularly through the initial transient.

A number of factors contribute to timbre. The material and construction of an instrument, the way it is played (bowing, plucking, striking), and the sound source (voice, electronic synthesis) all affect the harmonic structure and temporal envelope. Recording, processing, and listening context further modify timbre.

Perception of timbre is multidimensional and can be described with terms such as bright, dark, warm, harsh, mellow, or creamy. Because timbre blends spectral content with dynamic and articulatory cues, it is not reducible to a single quantity. Researchers quantify timbre using measures such as spectral centroid, spectral flux, roughness, inharmonicity, and temporal envelope descriptors.

Timbre plays a central role in music, informing instrument design, orchestration, synthesis, and sound engineering. The study of timbre integrates acoustics, psychoacoustics, and music perception to explain how listeners differentiate and interpret complex sounds.