Pink Noise

Pink noise is a variant of white noise with equal energy at every octave. It is the result of passing  white noise through a 3 dB per octave low pass filter.This test signal spans between 20 Hz and 20 kHz. The output level is variable from -72 dBu to -4 dBu, -74 dBV to -6 dBV. Pink noise is used in testing and calibrating loudspeakers and sound systems, as well as analyzing and equalizing the acoustical characteristics of room environments.