Long bass wavelengths relative to cabinet size make bass diffraction negligible.

Evidence

Diffraction at bass frequencies is generally less of a problem, because the wavelengths are large compared with the cabinet size. However, if the main cabinet contains midrange units, then it must also take account of diffraction effects. As this enclosure must also contain the bass units and must sit on a surface, it is not possible to have a spherical enclosure. Instead, the curvature can only be arranged in the vertical axis. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2160

Categorization

• DEFINE: Clarifies why diffraction scales with wavelength-to-obstacle ratio rather than absolute size — the core psychoacoustic principle for edge effects.
• XREF: connects to: Long bass wavelengths diffract less because they exceed cabinet dimensions — David Howard, Jamie Angus, coustics and Psychoacoustics, 2212