Acoustic diffusion needs surface bumps sized between an eighth and a half wavelength

Evidence

Sound that is incident on an object is not just diffracted around it—some of the incident energy will be reflected, or scattered, from the side facing the incident wave, as shown in Figure 1.47. As in the case of diffraction, it is the size of the object with respect to the wavelength that determines how much and in what way the energy is scattered. When the object is large with respect to the wavelength, most of the sound incident on the object is scattered according to the laws of reflection, and there is very little spreading or diffraction of the reflected wave, as shown in Figure 1.48. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 435 (#expands, via linked claim)

Categorization

Category: Causal Relationships

Related

• Effective sound diffusion requires bumps sized between an eighth and half a wavelength. (similarity 0.92)
• Element-based acoustic models scale poorly as wavelength shortens (similarity 0.90)
• How bumps reflect sound depends on bump height relative to wavelength. (similarity 0.90)
• Regularly spaced surface bumps diffuse sound only at specific frequencies (similarity 0.89)
• Flat surfaces reflect low-frequency sound specularly but scatter high-frequency sound (similarity 0.89)
• Effective sound diffusion demands surface depths proportional to the target wavelength (similarity 0.89)
• Whether a surface reflects or scatters waves depends on roughness relative to wavelength (similarity 0.89)
• Reflection and diffraction of sound both depend on object size relative to wavelength (similarity 0.87)
• Any change in surface reflectivity, not just bumps, causes sound diffusion (similarity 0.86)
• Sound bends around obstacles through a process called diffraction (similarity 0.85)
• Reflection from a bumpy surface depends on bump height relative to wavelength. (similarity 0.85)
• Sound diffracts strongly only when wavelengths exceed opening size (similarity 0.85)
• Acoustic wavelength size relative to objects governs how sound interacts with them (similarity 0.84)
• Lower frequencies diffract more around obstacles than higher frequencies do (similarity 0.84)
• Sound scatters or diffracts around loudspeakers based on wavelength relative to size (similarity 0.83)

Broader Connections

• How bumps reflect sound depends on bump height relative to wavelength. #expands (0.85)
• Acoustic wavelength size relative to objects governs how sound interacts with them #expands (0.85)
• Diffusion depth scales proportionally with wavelength, so lower frequencies demand deeper surfaces #expands (0.80)
• Reflection and diffraction of sound both depend on object size relative to wavelength #expands (0.80) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 435
• The diffuse field assumption underpins room acoustics predictions but fails at low frequencies #qualifies (0.72)