Diffuse-field regions sound best because modes are minimal and level is even

Evidence

Another name for these standing waves in a room is resonant modes, and the frequencies at which they occur are known as “modal frequencies.” Because the modes are spatially static, there will be a strong variation of sound pressure level as one moves around the room, which is undesirable. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1953 (#corroborates, via linked claim)

Calculation of the Schroeder frequency assumes meaningful reverberation times, a strongly diffuse sound field and a volume unimpeded by large objects (furniture and people are large objects in small rooms). Small listening rooms and recording control rooms are too absorptive to have a meaningful diffuse sound field and a reverberation time—a reflection decay time would be a better description at middle and high frequencies and resonance ringing time at low frequencies. — Toole, Floyd E, Sound reproduction- the acoustics and…, 477 (#contradicts, via linked claim)

Categorization

• XREF: connects to: Isolated low-order axial modes cause the worst and most treatable problems; Pure diffuse-field calibration yields inadequate bass and low preference ratings; The diffuse field assumption underpins room acoustics predictions but fails at low frequencies (+2 more)

Broader Connections

• The diffuse field assumption underpins room acoustics predictions but fails at low frequencies #qualifies (0.85)
• Spatially static resonant modes cause sound level to vary across a room #corroborates (0.85) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1953
• Small listening rooms lack diffuse reverberation and contain only early reflections #contradicts (0.78) — Toole, Floyd E, Sound reproduction- the acoustics and…, 477