A transition frequency separates modal from ray acoustical behavior in rooms
Evidence
Between the orderly low-frequency room resonances, and the different higher frequency reflection/ray-acoustical behavior, is a transition zone, the middle of which, in large rooms such as concert halls and auditoria, would be defined as the Schroeder frequency or, as Schroeder himself calls it, the cross-over frequency fc (Schroeder, 1954, 1996): where T is the reverberation time in seconds, and V is the volume of the enclosure in cubic meters. The multiplier constant changed from the original 4000 to 2000 in the 1996 paper, emphasizing that this is not a precision calculation. — Toole, Floyd E, Sound reproduction- the acoustics and…, 475
Categorization
- DEFINE: Defines the Schroeder cross-over frequency fc = 2000·sqrt(T/V), the formal boundary between room modes and ray acoustics.
- corroborated: 2 independent passages support this claim — Toole, Floyd E, Sound reproduction- the acoustics and…, 475
- XREF: connects to: A single recorded click can predict any sound’s behavior in a space; Room resonances shift from isolated to overlapping at the Schroeder frequency; Hard-walled rooms behave as three-dimensional resonators with many audible modal frequencies — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 291 (+17 more)
Broader Connections
- Room acoustics shift from standing waves to irregular interference as frequency rises
#exemplifies(0.90) — , Toole, Floyd E - Sound reproduction-…, 626 - Room acoustical behavior changes across a broad transition region, not at one frequency
#qualifies(0.85) - Modal decay analysis governs room acoustics below the critical frequency
#expands(0.80) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2038 - The diffuse field assumption underpins room acoustics predictions but fails at low frequencies
#expands(0.75) - Room modal bandwidths depend on decay time, not frequency
#complicates(0.70) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2012