For short wavelengths, walls only confine sound rather than amplify its power.

Evidence

Waterhouse (1955) extended work by Rayleigh (1964) and confirmed experimentally that the power output of a source is affected by the presence of boundaries, for example the walls in a room. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2134 (#contradicts, via linked claim)

Categorization

• XREF: connects to: Room boundaries alter a sound source’s radiated power, not just its perceived sound — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2134; A reflecting wall doubles total sound power output from any source

Broader Connections

• Room boundaries alter a sound source’s radiated power, not just its perceived sound #contradicts (0.85) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2134
• A reflecting wall doubles total sound power output from any source #contradicts (0.82)