An audio signal processor receives a plurality of encoded multi-channel audio signals. A multi-channel decoder (105) decodes a first encoded multi-channel signal to generate a first decoded multi-channel signal. A generator (109) generates an encoded further audio signal by selecting audio encoding data from at least a second encoded multi-channel audio signal such that a number of channels of the encoded further audio signal comprising audio encoding data from the second encoded multi-channel audio signal is less than a number of channels in the second encoded multi-channel signal. Thus, a channel reduction is performed in the encoded data domain. A further decoder (111) generates a further decoded signal by decoding the further encoded audio signal. A combiner (107) combines the first decoded multi-channel signal and the further decoded signal to generate a multi-channel output signal. An exciting user experience can be provided while maintaining low complexity and resource usage.