MC RO

Room acoustics, made visible

The room sings back

Walls turn certain low notes into places. The same frequency can boom in one corner and almost disappear a few steps away.

Choose a frequency. Then move the yellow point through the room.

Red and blue areas have high relative pressure with opposite signs. The yellow band marks a node. The yellow point is the listening position.

(1,0,0) 40.8 Hz axial
near a node
Room dimensions
Listening position
At this spot 31% of theoretical maximum pressure · between node and maximum

Low volume. Sound starts only when pressed.

20–200 Hz

The walls’ score

Each mark is one of the room’s own frequencies between 20 and 200 Hz. Nearby marks can create a crowded bass region.

Selected mode

Why a room has notes

A mode fits an integer number of half wavelengths between the walls. The three numbers count the variations along length, width and height.

f = c/2 × √[(n/L)² + (m/W)² + (p/H)²]
Model, sources and limits

The ideal model and the real room

The visualization calculates modes in a rigid-walled rectangular enclosure and uses a speed of sound of 343 m/s. Relative pressure is the product of cosine functions along the three axes.

A real room adds doors, windows, furniture, absorption, flexible walls, speaker position and air temperature. These change amplitudes and can shift frequencies slightly. Use the result for intuition, then measure the room before making treatment decisions.

Model checked 14 August 2026. Review when the formula, sources or declared limits change.

  1. MIT OpenCourseWareRoom acoustics & reverberationStanding waves and modes between parallel walls.
  2. University of IowaAcoustic Spectroscopy of RoomsThe three-dimensional formula for rectangular room frequencies.
  3. Purdue UniversityModes in a rectangular roomA visual example of pressure sign and amplitude.