inharmoniciteitscoëfficiënt

Inharmoniciteitscoëfficiënt refers to a measure of how much the overtones of a musical instrument deviate from perfect integer multiples of the fundamental frequency. In ideal, perfectly harmonic instruments, the first overtone is twice the fundamental, the second overtone is three times the fundamental, and so on. However, real-world instruments, especially those with strings like pianos and guitars, exhibit inharmonicity. This occurs due to the stiffness of the vibrating material. When a string vibrates, its stiffness causes the higher overtones to be slightly sharper than their ideal harmonic frequencies.

The inharmonicity coefficient quantifies this deviation. A higher coefficient indicates greater inharmonicity, meaning the overtones are more significantly stretched away from the harmonic series. This effect is more pronounced in shorter, thicker strings or strings under higher tension, which is why it is a notable characteristic of pianos, particularly in the bass register. While excessive inharmonicity can be undesirable, a certain degree of it is often considered part of the characteristic timbre or "color" of an instrument. The precise value of the inharmonicity coefficient can vary between different instruments and even between different notes on the same instrument. This phenomenon is a key consideration in the design and tuning of musical instruments.