The Audio Expert, 2nd Edition

Chapter 20

Room Shapes, Modes, and Isolation

Two of the most important properties of a room are its size and shape, which directly affects its low-frequency behavior. Generally speaking, large rooms are better acoustically than small rooms, because not only are the walls and ceiling farther away from listeners and microphones, which reduces the strength of reflections, but in large rooms the mode frequencies are closer together. Most acoustics experts recommend a minimum volume of at least 2,500 cubic feet for rooms where music will be produced with high quality.

A room mode—short for mode of vibration—is acoustics-speak for a natural resonance whose frequency depends on the distance between two opposing surfaces. For example, a room that’s 14 ...