For a given frequency, the time required for the average sound-energy density, originally in a steady state, to decay to one millionth of its initial value after the source is stopped (i.e. 60 dB).
"Dear CVC Productions: I waited for years for an obscure Japanese musician's work to be released on a CD. No luck. So I sent my three old, long-play records to CVC for conversion. I now am the proud owner a single CD with the cream cuts off those three albums! Very satisfying. Good work guys! Thank you! "