Inharmonilisus

Inharmonilisus is a term used in acoustics and music theory to denote a property of a sound in which the spectrum contains energy at frequencies that do not align with a simple harmonic series of the fundamental pitch. Sounds exhibiting inharmonilisus are perceived as less consonant and more rough or metallic, depending on the distribution of nonharmonic partials.

The term is a neologism formed from the prefix in- and the root harmonilisus, inspired by the Latin harmonilis meaning harmonious. It was proposed in contemporary discussions of timbre and has since appeared in theoretical writings and experimental sound design.

Characteristics: Inharmonilisus is characterized by partial frequencies that deviate measurably from integer multiples of the fundamental. This deviation is quantified by an inharmonicity metric; high values correlate with rough timbres as heard in bells, bowed metals, and some synthetic spectra. It often interacts with overtone amplitude and decay to shape perceived consonance.

Measurement and interpretation: Analysts use Fourier analysis, spectrograms, and inharmonicity indices to identify inharmonilisus. In practice, it influences instrument design, such as string stiffness and material choice, and affects tuning stability in tempered instruments.

Applications and reception: In harmonic theory, inharmonilisus is often treated as a complicating factor; in avant-garde music and sound design, it is used deliberately to create color and texture. The term remains more common in speculative or educational contexts than in standard encyclopedic reference.

Related topics include inharmonicity, timbre, spectrum, consonance, and overtone.