Sound near walls or large vessels is enhanced by scattering regardless of resonator tuning

Evidence

So far we have only considered sound in isolation, and we have seen that sound has velocity, frequency and wavelength and reduces in intensity in proportion to the square of the distance from the source. However, sound also interacts with physical objects and other sound waves and is affected by changes in the propagating medium. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 322 (#expands, via linked claim)

The NFC mechanism was well understood by Lord Rayleigh. However, it seems that ever since Rayleigh, the usual casual explanations, something like “there is a resonator near a source and it resonates! Resonators get loud on resonance!” have gradually dulled the mind and the level of understanding. The difficulty with the casual statement is that it is not an explanation, and, worse, it is false in some circumstances. For example, there can be a suppression of the sound if a monopole source, instead of a dipole or quadrupole source, is brought near the resonator. Capture, phase shifting, and reradiation still occurs, but now the phase-shifted, reradiated sound finds itself more or less destructively interfering with the direct sound from the monopole, depending on its distance to the resonator. It is quite shocking to hear this failure if one believes that any sound source should be amplified by proximity to a resonator. Dramatic amplification follows only from breaking a short-circuiting sound source. — Eric J. Heller, Why You Hear What You Hear- An…, 1889 (#contradicts, via linked claim)

Categorization

• XREF: connects to: Proximity to a resonator suppresses, rather than amplifies, monopole sound sources — Eric J. Heller, Why You Hear What You Hear- An…, 1889; Sound propagation depends on interactions with objects and the medium — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 322; Horn bells boost lower frequencies where wall friction dominates resonance enhancement (+1 more)

Broader Connections

• Proximity to a resonator suppresses, rather than amplifies, monopole sound sources #contradicts (0.80) — Eric J. Heller, Why You Hear What You Hear- An…, 1889
• Sound propagation depends on interactions with objects and the medium #expands (0.80) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 322