What term describes a tone with a single frequency of vibration?

• A. Pure tone
• B. Complex tone
• C. Noise
• D. Timbre

Answer: (A)

A tone with a single frequency of vibration is called a pure tone. This is the simplest kind of sound, represented by a sine wave that has one stable frequency and no harmonic components. Because it contains only one frequency, its pitch is clear and isolated. In contrast, a complex tone contains several frequencies (the fundamental plus harmonics), giving a richer sound; noise covers a broad, random spectrum with many frequencies, producing a hiss-like quality; and timbre is the perceptual quality that lets us distinguish different sounds at the same pitch based on the overall spectral content and how those frequencies evolve over time.