An encoder for mixing a plurality of independent mono audio channels into a stereo recording and generating a restricted set of additional parameters used to master an audio track of a storage device is described. The plurality of independent mono audio channels are constructed such that the storage device can be played using an optical disk player so that in a first mode all of the plurality of independent mono audio channels are played as the stereo recording and in a second mode at least one of the plurality of independent mono audio channels can be unmixed and the stereo recording played with at least one mono audio channel removed. A corresponding decoder and an audio system comprising such encoder and decoder are also described.