Modal absorption is frequency dependent, stretching decay time at standing-wave frequencies
Evidence
This reduction in absorption is strongly frequency dependent and results in less absorption and therefore a longer decay time at the frequencies at which standing waves occur. — David Howard, Jamie Angus, coustics and Psychoacoustics, 2040
Categorization
Category: Causal Relationships
- XREF: Connects to the general psychoacoustic theme that resonance colors sound; relevant to how room modes distort perceived music.
Related
- Standing-wave modes produce several decay times, leaving excess energy at modal frequencies (similarity 0.92)
- Modal bandwidths break diffuse-field assumptions when sound paths exceed the mean free path (similarity 0.86)
- Room materials’ absorption coefficient varies with frequency (similarity 0.86)
- Room modes produce multiple decay times instead of a single exponential reverberation (similarity 0.86)
- Modal decay differs from diffuse decay because reflection paths are fixed, not random. (similarity 0.86)
- A room mode’s length relative to mean free path sets its decay time (similarity 0.84)
- The diffuse field assumption underpins room acoustics predictions but fails at low frequencies (similarity 0.81)
- Modal decay analysis governs room acoustics below the critical frequency (similarity 0.81)
- Modal strength depends on reflection count, not just mode type (similarity 0.80)
- Absorption dampens modes and enhances any additional room remedies (similarity 0.80)
- Exciting multiple room modes instead of one reduces frequency and spatial sound variation (similarity 0.80)
- Absorption at each reflection governs how fast reverberation decays (similarity 0.80)
- Every room has a frequency below which modal effects break the diffuse-field assumption (similarity 0.80)
- Modal behavior intensifies as wavelength approaches the room’s mean free path (similarity 0.80)
- Room sound homogeneous decay holds for typical rooms but can be engineered away (similarity 0.79)
Broader Connections
- Standing-wave modes produce several decay times, leaving excess energy at modal frequencies
#corroborates(0.85) — David Howard, Jamie Angus, coustics and Psychoacoustics, 2042 - Room absorption shrinks mode bandwidth and flattens standing wave peaks
#expands(0.80) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2008 - Modal decay time depends on mode length relative to the diffuse-field mean free path
#expands(0.78) — David Howard, Jamie Angus, coustics and Psychoacoustics, 2050 - Modal waves absorb less because their incidence is not random
#qualifies(0.75) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1998