Dipole sources amplify through near-field capture, phase shift, and reemission by a resonator

Evidence

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 (#complicates, via linked claim)

Categorization

• XREF: connects to: Spontaneous emission spacing reflects the frequency step producing 180 degrees of phase shift.; Phase relationships between subcomponents shape a source’s radiation pattern; Driven resonator phase shifts 180 degrees across its resonance (+4 more)

Related

• Marimba resonators amplify sound by capturing near-field energy that would otherwise short-circuit (similarity 0.88)
• Resonators amplify sound by capturing near-field energy and reradiating it with a phase shift (similarity 0.87)
• Driven resonator phase shifts 180 degrees across its resonance (similarity 0.84)
• Proximity to a resonator suppresses, rather than amplifies, monopole sound sources (similarity 0.84)
• Sound near walls or large vessels is enhanced by scattering regardless of resonator tuning (similarity 0.83)
• Oppositely phased resonators short-circuit each other and prolong sound decay. (similarity 0.82)
• Driving a sounding board near a clamped edge produces antiresonance (similarity 0.82)
• Nearby walls amplify monopole but not dipole sound sources (similarity 0.80)
• Phase relationships among source components shape far-field radiation directionality (similarity 0.80)
• Nearby reflecting surfaces constructively pile up wave reflections to amplify sound (similarity 0.79)
• Resonators amplify quiet near-field vibrations far more than direct air-column strikes. (similarity 0.78)

Broader Connections

• Marimba resonators amplify sound by capturing near-field energy that would otherwise short-circuit #exemplifies (0.95)
• Proximity to a resonator suppresses, rather than amplifies, monopole sound sources #complicates (0.80) — Eric J. Heller, Why You Hear What You Hear- An…, 1889
• Mutual resonance between sources boosts combined power beyond their sum #expands (0.75)
• Resonance requires confinement of previously emitted amplitude #complicates (0.75)