What is the relationship of frequency to absorption?

• A. If frequency is halved, absorption is doubled.
• B. If frequency is doubled, absorption is doubled.
• C. If frequency is doubled, absorption is halved.
• D. The rate of sound absorption is not frequency dependent.

Answer: (B)

Absorption of sound grows with frequency. Higher-frequency waves interact with air and material more strongly, undergoing more damping per cycle and converting more energy into heat. In many basic models, this relationship is treated as roughly proportional, so doubling the frequency leads to about twice the amount of energy absorbed per unit area. That’s why increasing frequency tends to increase absorption, making the statement that doubling frequency doubles absorption a reasonable simplifying assumption. The idea that absorption is independent of frequency or that it decreases with frequency doesn’t match how dampening typically behaves in common materials and air.