Painted brick absorbs only about 1% of incident sound while wood absorbs about 15%

Evidence

Why do walls absorb sound? What happens to the energy, and how may we understand the different sound absorption of a brick wall and one made of wood? (A painted brick wall absorbs only about 1% of the sound incident on it; wood typically about 15%.) — Eric J. Heller, Why You Hear What You Hear- An…, 2437