Panning law
Panning law, or panning rule, is a recording and mixing principle that states that any signal of equal amplitude and phase that is played in both channels of a stereo system will increase in loudness up to 6.02 dBSPL, provided there is perfect response in the loudspeaker system and perfect acoustics in the room. Often, the acoustic summing of a room and system are inferior to the ideal, so the specific relative level will increase from −3 dB to 0 dB as the mono signal is panned from center to hard left or right.