The Schroeder frequency miscalculates for small furnished rooms but the transition is real

Evidence

Therefore, in small rooms, especially those with large furnishings, the strictly applied Schroeder frequency calculation is mismatched. The calculated value may be in error, as noted by Baskind and Polack (2000). For the room used in the measurements of Figure 2.6(c) the Schroeder frequency is 129 Hz (T = 0.32 s, V = 76.9 m3). This appears to be on the low side, because the large undulations in the curves have not diminished. However, no matter how it is identified, or what it is called, the transition region is real, and it is necessary to take different approaches to dealing with acoustical phenomena above, within, and below it. It is unrealistic to think that room performance changes at a single frequency. — Toole, Floyd E, Sound reproduction- the acoustics and…, 478

Categorization

• QUESTION: Worth tracing: what exactly accounts for the discrepancy between the computed 129 Hz and the visually observed transition, and does the 4000 vs 2000 constant resolve it.