What is grey noise?
Grey noise starts from the same equal-power spectrum as white noise, but has its extreme highs and very low sub-bass gently rolled off — the parts of the spectrum that tend to feel harshest or most fatiguing over a long listen.
The result is a softer, smoother static that many people find more comfortable than plain white noise for extended sessions.
Tips for using grey noise
A good starting point if white noise feels too sharp or tiring on your ears after a while. If you want a touch more presence back, white noise is the sharper original this is based on.