Amplitude diffusion gratings have no low-frequency limit, only a high-frequency one

Evidence

Thus amplitude reflection gratings consist of a surface treatment which consists of strips of absorbing material, whose width is less than λ 2 at the highest frequency of use, laid out in a pattern in which strips of absorber represent zero and strips of reflecting wall represent 1 (see Figure 6.52). Note that because we are not depending on depth we do not have a low-fre­ quency limit to the range of diffusion, only a high-frequency limit which is a function of the width of the strips. — David Howard, Jamie Angus, coustics and Psychoacoustics, 2153

Categorization

• DEFINE: Lays out what an amplitude reflection grating actually is — the surface treatment mechanism and its key property.
• XREF: Contrasts with phase reflection gratings later in the chapter and with the depth-based diffusers discussed earlier. — connects to: Effective low-frequency diffusion requires physically deep wells, about 34 cm for 500 Hz — David Howard, Jamie Angus, coustics and Psychoacoustics, 2143