A multi-channel audio encoding method based on an overall encoding procedure involving at least two signal encoding processes, including a first, main encoding process and a second, auxiliary encoding process, operating on signal representations of a set of audio input channels of a multi-channel audio signal, wherein said method includes: - encoding a first signal representation of said set of audio input channels of said multi-channel audio signal in said first, main encoding process in a first, main encoder; - performing local synthesis in connection with said first, main encoding process to generate a locally decoded signal including a representation of the encoding error of the first, main encoding process; - applying at least said locally decoded signal as input to said second, auxiliary encoding process; - encoding at least one additional signal representation of at least part of said audio input channels of said multi-channel audio signal in said second, auxiliary encoding process in a second, parametric multi-channel encoder, while using said locally decoded signal as input to said second, auxiliary encoding process; - generating at least two residual encoding error signals defining a compound residual that includes representations of the encoding errors of both the first and second encoding processes; - performing compound residual encoding of said residual error signals in a further complementary encoding process including compound error analysis based on correlation between said residual error signals, wherein said compound residual encoding includes decorrelation of the correlated residual error signals by means of a transform to produce corresponding uncorrelated error components, quantization of at least one of said uncorrelated error components, and quantization of a representation of said transform. - encoding a first signal representation of said set of audio input channels of said multi-channel audio signal in said first, main encoding process in a first, main encoder; - performing local synthesis in connection with said first, main encoding process to generate a locally decoded signal including a representation of the encoding error of the first, main encoding process; - applying at least said locally decoded signal as input to said second, auxiliary encoding process; - encoding at least one additional signal representation of at least part of said audio input channels of said multi-channel audio signal in said second, auxiliary encoding process in a second, parametric multi-channel encoder, while using said locally decoded signal as input to said second, auxiliary encoding process; - generating at least two residual encoding error signals defining a compound residual that includes representations of the encoding errors of both the first and second encoding processes; - performing compound residual encoding of said residual error signals in a further complementary encoding process including compound error analysis based on correlation between said residual error signals, wherein said compound residual encoding includes decorrelation of the correlated residual error signals by means of a transform to produce corresponding uncorrelated error components, quantization of at least one of said uncorrelated error components, and quantization of a representation of said transform.