White Noise

White noise is a random signal with constant spectral density across all frequencies, meaning equal energy per hertz. On an octave-band analyzer, white noise increases by 3 dB per octave because each successive octave contains twice as many hertz. White noise sounds "bright" or "hissy" compared to pink noise because of its relatively higher high-frequency content. In acoustics, white noise is used in sound masking systems (often filtered to a desired spectrum), random noise generators for electronic testing, and as a basis for deriving other noise colors. For room acoustic measurements, pink noise is generally preferred over white noise because it matches the logarithmic frequency bands used in analysis. However, white noise is mathematically simpler and is the starting point for many signal processing applications. Sound masking systems typically filter white noise into a shaped spectrum optimized for speech privacy.