Reflection and diffraction of sound both depend on object size relative to wavelength
Evidence
In 1950, Olson (1969) demonstrated, experimentally, that the enclo sure shape and size significantly affect the frequency response of a loud speaker, due to diffraction effects. These diffraction effects can occur at any frequency where the wavelength is of similar size, or smaller than the box. This means that they can occur in any small enclosure, such as a top mounted tweeter. They can also occur in the main cabinets if there are drivers whose frequency ranges produce wavelengths of appropriate dimen sions relative to the box sizes. — David Howard, Jamie Angus, coustics and Psychoacoustics, 2198 (
#expands, via linked claim)
Categorization
- corroborated: 2 independent passages support this claim
- XREF: connects to: Reflection from rough surfaces smooths detail once wavelengths exceed roughness; Small vibrating objects radiate weak sound because source size is far under one wavelength; A piston’s radiation efficiency depends on size relative to wavelength, not absolute size (+17 more)
Broader Connections
- How bumps reflect sound depends on bump height relative to wavelength.
#expands(0.95) - Effective sound diffusion demands surface depths proportional to the target wavelength
#exemplifies(0.85) - Loudspeaker enclosure shape and size alter frequency response via diffraction
#expands(0.85) — David Howard, Jamie Angus, coustics and Psychoacoustics, 2198 - Larger speaker size relative to wavelength enables higher directivity
#exemplifies(0.82)