Concert hall surfaces reflect low but scatter high frequency sound

Evidence

These statements apply to sound waves reflecting from a hard surface. A surface with only small irregularities but otherwise flat reflects low-frequency, long-wavelength sound in a mirror-like fashion. The same surface will reflect high-frequency, short-wavelength sound diffusely. These facts have not been lost on designers of acoustic spaces, especially concert halls. — Eric J. Heller, Why You Hear What You Hear- An…, 171

Categorization

• XREF: Directly relevant to architectural acoustics and concert hall design, which resonates with the reader’s existing soundscape listening.
• SEED: Could be an angle: how the same physics governs why bathroom mirrors look shiny and why concert halls scatter high frequencies — wavelength as the master lens.