Low frequencies can be tremendously powerful, capable of flexing walls, ceilings and occasionally, floors. Flexure of this type is termed diaphragmatic action. To illustrate this concept, think of the room as a small box. If the box is made of cardboard, the walls vibrate easily. The same box made of concrete would exhibit little movement.
Diaphragmatic action dissipates low frequencies, robbing the bass of both impact and extension.
An ideal room would have absolute rigidity and infinite mass. The bass reproduction in the control room was absolutely the cleanest, tightest and most powerful I have yet experienced. Although the studio monitors and electronics in use were inferior to many of today s better hi-end audio systems, listening to this system with master tapes was truly a religious experience. Our goal then, is to reduce the amount of diaphragmatic action in the listening room. We can accomplish this task by increasing the mass and rigidity of all surfaces within the listening environment.