How does a simple tone differ from a complex tone?

In the study of acoustics, the distinction between a simple tone and a complex tone is defined by their frequency composition:

• Simple Tone: Also known as a pure tone, this consists of only one frequency. Because it lacks additional components, it has a clear, pure quality, such as the sound produced by a tuning fork.12
• Complex Tone: This consists of two or more simple tones sounding simultaneously. The lowest frequency in this combination is called the fundamental, while the additional frequencies are known as overtones. When these overtones are exact multiples of the fundamental frequency, they are referred to as harmonics.13

The presence, number, and relative intensities of these overtones determine the timbre—or tone color—of a sound. This is why different instruments playing the same fundamental pitch sound distinct from one another; each instrument emphasizes a unique combination of overtones. While a simple tone has a uniform quality, a complex tone’s timbre is shaped by its specific harmonic structure.243