Which definition best describes harmonics in sound?

Harmonics in sound are defined as subsequent frequencies that are related to a fundamental frequency. When a sound is produced, it typically doesn't just produce a single frequency; instead, it generates a complex waveform made up of the fundamental frequency and its harmonics. These harmonics are integer multiples of the fundamental frequency, contributing to the overall richness and timbre of the sound. For example, if the fundamental frequency is 100 Hz, the harmonics could be 200 Hz, 300 Hz, and so on. This characteristic is crucial in music and audio processing as it defines the tonal quality of the sound, distinguishing different musical instruments and voices despite them playing the same note.

Understanding harmonics is essential for hearing aid fitting and dealing with sound amplification, as it aids in shaping the sound output to be more natural and appealing to the listener. This highlights the complexity of sound and is a foundation for both music theory and audio engineering.