Sones are a unit of how loud a sound is perceived. The sone scale is linear. Doubling the perceived loudness doubles the sone value. In acoustics, loudness is the subjective perception of sound pressure. The study of apparent loudness is included in the topic of psychoacoustics and employs methods of psychophysics  <wikipedia>. GOOGLE DEFINITION: What is a sone? A sone is a measure of loudness. The higher the sone rating