This document specifies the methods for measuring the battery duration at defined sound pressure levels for continuous music playback of battery powered loudspeaker equipment. A primary battery or secondary battery can be used as a power source for the loudspeaker and its composite equipment. In case of composite equipment this method for the measurement of battery duration can be applied under the condition of powered loudspeaker playback only. NOTE Loudspeakers designed for short hearing distance are not in the scope of this document.