Acoustic length scales are set by wavelength, not absolute distance.

Evidence

In acoustics, the wavelength is often used as the “ruler” for measuring length rather than meters, feet or furlongs, because many of the effects of real objects, such as rooms or obstacles, on sound waves are dependent on the wavelength. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 149

Categorization

• DEFINE: Explains why wavelength functions as the natural measuring ruler for acoustic environments — clarifies a core terminology habit.
• corroborated: 2 independent passages support this claim — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 149