Which two characteristics mainly define the quality of a sound wave?

The quality of a sound wave is primarily defined by its timbre and harmonics. Timbre refers to the unique color or quality of sound that allows us to distinguish between different sound sources, even when they are producing the same pitch. For example, a note played on a piano sounds different from the same note played on a guitar due to the unique timbre of each instrument.

Harmonics contribute to this as well; they are the overtones that occur alongside the fundamental frequency of a sound. These overtones shape the overall sound quality and richness, helping to create the distinctive sound that characterizes musical instruments. Together, timbre and harmonics allow listeners to perceive the complexity and character of sound beyond just pitch and loudness, making them essential in assessing sound quality.