Room standing waves dominate below the Schroeder frequency while the loudspeaker controls above it

Evidence

Above about 400 Hz the curves are essentially identical, and the prediction aligns well with the measurements. Below this the effects of standing waves in the room dominate, and the locations of the loudspeaker and the listener/microphone determine the acoustical coupling at different frequencies. The predicted curve provides an estimate of the upper limit of the steady-state sound levels, but destructive interference in the standing waves substantially reduces overall bass energy. Below about 400 Hz the room is the dominant factor; above it, the loudspeaker is substantially in control. The differentiation between the frequency regions above and below about 400 Hz will be discussed in the next section, but it is clearly associated with the well-known Schroeder frequency, which in small rooms is also called the transition frequency. — Toole, Floyd E, Sound reproduction- the acoustics and…, 185

Categorization

• DEFINE: Defines the Schroeder/transition frequency as the boundary where the room, not the loudspeaker, dominates the steady-state response.