Blue noise is essentially the opposite of Brown noise ? its energy is concentrated at the high end of the spectrum, meaning it's all treble and no bass. An example might be a hissing water spray. You'd most commonly use blue noise to minimize distortions during sound engineering.

Blue noise, also known as "azure noise," is a type of random signal where the power density increases with frequency. To the human ear, blue noise sounds like a high-pitched, very fine-grained hiss, similar to the sound of water spraying out of a high-pressure nozzle or the "shhh" sound made by a steam valve. It is the opposite of brown noise, which is deep and bass-heavy. In the world of audio engineering and digital imaging in 2026, blue noise is highly valued for its "randomness" properties. In computer graphics, "blue noise dithering" is used to create smooth gradients and reduce "banding" without creating distracting patterns, as the high-frequency nature of the noise is less visible to the human eye. In the world of sleep and focus, while white noise remains the most popular, some people prefer blue noise for masking high-pitched environmental sounds, such as bird chirping or distant sirens. It is generally considered more "energetic" and less "soothing" than pink or brown noise, making it more common in technical applications than in baby sleep machines or meditation apps.