Simple Explanation

A type of noise that contains all frequencies in the audio spectrum, each with the same energy level.

Concise Technical Definition

White noise is a random signal that spans the entire audio spectrum, with equal energy distributed across all frequencies. This gives it a constant power density at every frequency, resulting in a "hissing" sound. Compared with pink noise, white noise has more energy in the higher frequencies (treble), which makes it sound sharper and brighter. It is commonly used for sound masking, acoustical testing, and in electronic devices like radios and TVs.

Layman-Friendly Analogy

White noise is like the sound of a TV or radio tuned to an unused frequency, producing a constant "shhh" sound. It’s a mix of all the possible frequencies you can hear, all played at once, and it sounds like a hissing, static noise. Imagine the sound of a vacuum cleaner or a fan—it’s the same constant noise, with no particular pitch or tone.

Industry Usage Summary

White noise is widely used in audio applications, including sound masking, acoustical measurement, and as a reference signal for equipment testing. It is also commonly used in noise generators, sleep aids, and in studios for controlling sound environments. In sound masking, white noise helps to mask other environmental noises, making it useful in offices, recording studios, and hospitals. However, due to its higher treble content, white noise can be perceived as harsh compared with other types of noise, like pink noise, which is often preferred for certain audio applications.

Engineering Shortcut

A type of noise with equal energy at all frequencies, resulting in a "hissing" sound, often used in sound masking and audio testing.

Full Technical Explanation

White noise is a signal that contains all frequencies within the human audible range (typically 20 Hz to 20 kHz), each with the same power level. This gives it a flat frequency spectrum when plotted, meaning it has an equal amount of energy at all frequencies. The result is a sound that is often described as hissing or static-like. White noise differs from other types of noise, such as pink noise, by having a greater concentration of energy in the higher frequencies. While white noise can be useful for acoustical testing and sound masking, its treble-heavy nature can make it more intrusive than other noise types. It is commonly used for testing audio equipment or measuring frequency response and for applications like creating a neutral noise floor in a controlled environment.