Britannica Sources used in this answer

How do thicker strings change the sound and pitch of an instrument?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

Koto — stringed instrument A Japanese musician plucking the strings of a koto with the right hand to generate a pitch and pressing the strings with the left hand to alter the tone.

According to Mersenne’s laws, the fundamental frequency of a stretched string is inversely proportional to the square root of its mass per unit length. This means that as a string becomes thicker—thereby increasing its mass per unit length—its fundamental pitch decreases, assuming the length and tension remain constant.1

In the construction of stringed instruments, this principle is used to achieve a uniform sound across the instrument's range. By using thicker, heavier strings for lower notes and thinner, lighter strings for higher notes, makers can maintain relatively consistent tension across all strings, which helps prevent structural issues like warping.1

Additionally, the thickness of a string influences its timbre and harmonic content. For example, bass strings on a grand piano are often constructed by winding heavy wire with additional thin wire. This increased thickness makes the wires stiffer, which causes the overtones to deviate from ideal harmonics, resulting in a characteristic inharmonicity that contributes to the instrument's unique tone.1