A unit of loudness. A simple l-kHz tone, 40 dB above a listener’s threshold, produces a loudness of 1 sone. The loudness of any sound that is judged by the listener to be n times that of the 1 sone tone is n sones.
"Thank you for the quality work on the lp's, the sound quality is excellent. I've been waiting about 15 years to hear those albums again (they are unavailable in any form, and were only made on lp briefly in 1984)."