Below the Schroeder frequency, the sound field is dominated by discrete room modes — individual resonances that create sharp peaks and nulls. Above the Schroeder frequency, modes are so densely packed that they blend into a more statistical, diffuse sound field. Room correction strategies differ above and below this frequency.
The Schroeder frequency is calculated from the room's volume and RT60. Larger, more reverberant rooms have lower Schroeder frequencies (better for mixing). Small, dead rooms have higher Schroeder frequencies (more of the spectrum affected by discrete modes). For a typical 12×10×8 ft bedroom, the Schroeder frequency is around 200 Hz.