timbre

Timbre IS a specific kind of property — an acoustic/auditory attribute. A competent speaker would describe timbre as a property of sound (Law 9).

Timbre as a concept exists to enable precise communication about acoustic sources — it provides the vocabulary to distinguish a violin from a flute playing the same note at the same volume. Without timbre, musicians and acousticians lose a critical dimension of musical discourse. Law 8d: timbre is built/maintained for the sake of communication.

Timbre is the quality that distinguishes different types of sound — it is the 'color' of a sound. Per Law 8 removal test: remove sound and timbre ceases to operate (there is no sound to have timbre). Timbre is not sound itself (not identity), but it is a property OF sound that needs its referent to function. Remove the referent and the property cannot operate.

Timbre is the quality distinguishing sound sources at the same pitch and loudness. It is defined by the overtone structure (which overtones exist, their amplitudes and evolution). Remove the concept of overtone and timbre loses its defining mechanism — it cannot distinguish sound qualities. Per Law 8 removal test: X stops operating without Y.

Timbre is the quality of sound that distinguishes different sources at the same pitch and loudness. It is determined by the frequency content (spectral envelope, harmonics) of a sound. Remove frequency and timbre cannot operate — the concept of timbre has no operating mechanism without frequency as its domain.

Timbre is the perceptual quality that distinguishes sounds of same pitch/loudness — determined by the spectral color (non-flat frequency content) of the sound. Remove spectral-coloration and timbre loses its explanatory mechanism; the concept cannot operate without it. This passes the removal test per Law 8: no spectral-coloration concept = no basis for timbre as a distinguishable quality.

Spectral contrast measures the difference between peaks and valleys in the power spectrum, producing a feature vector that captures the tonal characteristics of a sound. It was specifically designed and is maintained for the purpose of timbre analysis and musical instrument classification. The designed purpose is to serve timbre representation — spectral contrast → timbre follows the servant→master direction of SERVES.

Spectral rolloff is designed and maintained for the purpose of characterizing timbre — it captures the spectral centroid-like property of where energy concentrates, directly relating to the perceptual attribute of brightness/timbre. Per Law 8d: for whose sake? The rolloff feature points at timbre as its master.

Spectral centroid is built for the sake of timbre characterization — it provides a single number summarizing spectral shape, used to estimate perceived timbre brightness. Purpose is timbre analysis, Law 8d.