Confinement reflections amplify sources only when wave sign is preserved

Evidence

Proximity resonance results when a source of sound experiences almost immediate and constructive interference, due to some type of confinement or other nearby in-phase source (see, for example, sections 7.1 and 7.2). The confinement reflection must preserve the sign of the wave; otherwise, the reflection will suppress the source by destructive interference, or anti resonance. Proximity resonance makes possible large amplifications in the throat of horns (section 7.3) and the reproducer of a gramophone (figure 7.6), where many reflections from close-by surfaces pile up constructively and lead to large enhancements of the amplitude and the power. — Eric J. Heller, Why You Hear What You Hear- An…, 886

Categorization

• DEFINE: Defines proximity resonance and anti-resonance as paired mechanisms.