Abstract: A combined signal (Z) is provided as an additive mix of a secondary audio signal (Y) and a phase-inverted reduced primary signal (Xm?) obtained from a primary audio signal. The secondary signal (Y) can be restored from the primary (X) and the combined (Z) signal by additively mixing the latter with a reduced primary signal (Xm) obtained from the primary signal. This coding approach allows a supplementary audio service, in particular an audio description/video description to be distributed alongside with a multi-channel audio signal at low extra bandwidth or storage cost.