Diffraction occurs around solid objects as well as through openings.

Evidence

As well as occurring through openings, diffraction also happens around solid objects; one could consider them to be antiopenings, as shown in Figures 1.45 and 1.46. Here the wave diffracts around the object and meets behind it. The effect is also a function of the size of the object with respect to the wavelength. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 427

Categorization

• DEFINE: Introduces the ‘antiopening’ framing for how objects diffract sound waves.
• corroborated: 2 independent passages support this claim — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 427
• XREF: connects to: Cabinet edges and centered drivers create diffraction that smooth curves minimize — David Howard, Jamie Angus, coustics and Psychoacoustics, 2217