Effective low-frequency diffusion requires physically deep wells, about 34 cm for 500 Hz

Evidence

As we have seen, these sequences achieve their performance by spreading the phase of the reflected wavefront over at least one cycle of the incident wavefront. In order to do this, their maximum depth must be λ 2 at the lowest design frequency. This means that to achieve diffusion a reasonable depth is required. For example, to have effective diffusion down to 500 Hz a depth of 34 cm (13.5 inches) is required. — David Howard, Jamie Angus, coustics and Psychoacoustics, 2143

Categorization

• XREF: connects to: Low-frequency sound diffusion requires impractically deep diffuser wells — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2096; Diffusion depth scales proportionally with wavelength, so lower frequencies demand deeper surfaces; Effective sound diffusion demands surface depths proportional to the target wavelength (+6 more)

Broader Connections

• Diffusion depth scales proportionally with wavelength, so lower frequencies demand deeper surfaces #expands (0.95)
• Practical diffusers need depth set by wavelength of the lowest frequency treated #expands (0.94) — , Toole, Floyd E - Sound reproduction-…, 488
• Diffuser depth must scale with the lowest frequency it can scatter. #expands (0.94) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2096
• Effective sound diffusion demands surface depths proportional to the target wavelength #expands (0.93)
• Low-frequency sound diffusion requires impractically deep diffuser wells #expands (0.90) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2096
• Even quarter-wavelength diffuser depths are too large for low frequencies #corroborates (0.88)
• Effective sound diffusers must be physically comparable in size to the waves they scatter #expands (0.85) — Toole, Floyd E, Sound reproduction- the acoustics and…, 1386
• Acoustic diffusion needs surface bumps sized between an eighth and a half wavelength #qualifies (0.78)
• Amplitude diffusion gratings have no low-frequency limit, only a high-frequency one #complicates (0.75) — David Howard, Jamie Angus, coustics and Psychoacoustics, 2153