Next time you see a product claiming "Super quiet: 50 dB!" ask for the Sone rating. A 2-sone fan is a peaceful retreat. An 8-sone fan is a jet engine in your kitchen. Understanding the difference saves your ears—and your sanity.

The term "sone" was coined by Stanley Smith Stevens, an American psychologist, in 1937. Stevens was studying the perception of sound and wanted to create a unit that would quantify loudness in a way that was more relatable to human perception.

If you’re designing a home theater, choosing a vacuum cleaner, or trying to figure out why your 50-watt amp sounds quieter than a friend’s 20-watt tube amp, you need to meet the .