Which statement about octave band analysis is true?

• A. It measures energy across a range of frequencies.
• B. It measures only a single frequency.
• C. It is used to evaluate visual signals.
• D. It cannot be used for hearing protection decisions.

Answer: (A)

Octave band analysis breaks the sound spectrum into bands that cover a range of frequencies and measures the energy within each band. This creates a profile of how much sound energy sits in the low, mid, and high frequency regions, rather than focusing on a single frequency. That frequency-by-frequency energy distribution is essential for hearing protection decisions, because different protectors work differently across frequencies and certain bands may pose more risk than others. By identifying which octave bands carry the most energy, you can select appropriate hearing protection, set exposure limits, or apply controls targeted at the problematic ranges. The other statements don’t fit because octave bands don’t isolate a single frequency, aren’t about visual signals, and are indeed used to inform hearing protection decisions.