Setup and calibration
38 percent rule
A placement guideline that puts the main listening position about 38 percent of the room length from the front or rear wall to sit in the smoothest bass.
The 38 percent rule places the primary seat at 0.38 times the room length from the front wall, or equivalently from the back wall. There the listener sits between the peaks and nulls of the first several length modes, so no single mode dominates.
A seat at the room's midpoint sits in the null of every even-order length mode, and a seat against the rear wall sits in the peak of all of them. Shifting a foot or two can change bass response by 10 dB at some frequencies.
For a 6 m long room, the rule puts the ears about 2.3 m from either wall. It is a starting point, not a law: verify with a measurement or the room mode calculator, and balance it against the viewing angle you want.
Related terms