A piston’s radiation efficiency depends on size relative to wavelength, not absolute size

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

• Sound-radiation efficiency depends on piston size relative to wavelength, not absolute size (similarity 0.85)
• Radiation directivity depends on wavelength relative to source size (similarity 0.85)
• Whether a surface reflects or scatters waves depends on roughness relative to wavelength (similarity 0.83)
• Acoustic wavelength size relative to objects governs how sound interacts with them (similarity 0.83)
• Element-based acoustic models scale poorly as wavelength shortens (similarity 0.82)
• Sound scatters or diffracts around loudspeakers based on wavelength relative to size (similarity 0.81)
• Small vibrating objects radiate weak sound because source size is far under one wavelength (similarity 0.81)
• Sound bends around obstacles through a process called diffraction (similarity 0.81)
• Acoustic diffusion needs surface bumps sized between an eighth and a half wavelength (similarity 0.80)
• Directivity depends on wavelengths fitting across the radiating aperture (similarity 0.80)
• Piston sound power scales with area squared, not linearly with area (similarity 0.80)
• Small loudspeakers radiate omnidirectionally because they are small relative to wavelength (similarity 0.79)
• Reflection and diffraction of sound both depend on object size relative to wavelength (similarity 0.79)
• Flat surfaces reflect low-frequency sound specularly but scatter high-frequency sound (similarity 0.79)
• Sound propagation depends on interactions with objects and the medium (similarity 0.79)

Broader Connections

• Small vibrating objects radiate weak sound because source size is far under one wavelength #exemplifies (0.95)
• Reflection and diffraction of sound both depend on object size relative to wavelength #expands (0.93) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 435
• Radiation directivity depends on wavelength relative to source size #corroborates (0.92)
• Acoustic wavelength size relative to objects governs how sound interacts with them #expands (0.90)
• Directivity depends on wavelengths fitting across the radiating aperture #corroborates (0.88)
• Shorter wavelengths scatter more strongly from small objects than longer ones do. #exemplifies (0.85)
• Dipole cancellation strength depends only on source spacing relative to wavelength #exemplifies (0.82)