The lowest frequency present in a complex tone is known as the...

• A. Fundamental frequency
• B. First harmonic
• C. Highest frequency
• D. Middle frequency

Answer: (A)

In a complex tone made up of several sine waves, the frequencies form a harmonic series, with the lowest frequency setting the pace at which the waveform repeats. That base frequency is what we call the fundamental frequency. It determines the perceived pitch, because the rest of the components are harmonics at integer multiples of this fundamental. While you might see the term “first harmonic” used to refer to the same lowest component in some contexts, the standard term that emphasizes its role in establishing pitch and the periodicity of the tone is fundamental frequency. The other options don’t fit because the highest or middle frequencies aren’t the base rate that defines the tone’s repetition, and there isn’t a separate standard term for a “middle” frequency.