Pink noise calibration (pink noise with all high bits) for home and car professional audio systems.It’s the same sound as when the cable TV operator has lost the signal.
Pink noise or 1/ƒ noise is a signal or process with a frequency spectrum such that the power spectral density is inversely proportional to the frequency. In pink noise, each octave carries an equal amount of noise power. The name arises from being intermediate between white noise (1/ƒ0) and red noise (1/ƒ2), more commonly known as Brownian noise..
more here: en.wikipedia.org/wiki/Pink_noise