A method for reconstructing a multi-channel audio signal in a decoder of a multi-channel audio processing system, comprising the steps of: receiving N frequency extended downmix signals comprising spectral coefficients corresponding to frequencies between a first and second cross-over frequency, k y, k x, and above the second cross-over frequency k x, wherein k x > k y; generating M upmix signals comprising spectral coefficients corresponding to frequencies above the first cross-over frequency k y by parametrically upmixing the N downmix signals into M upmix signals, and wherein the M upmix signals do not comprise frequencies below the first cross-over frequency k y, each of the M upmix signals corresponding to a respective one of M encoded channels, wherein 1<N<M; receiving a first waveform-coded signal comprising spectral coefficients corresponding to a subset of frequencies above the first cross-over frequency k y; receiving M second waveform-coded signals comprising spectral coefficients corresponding to frequencies up to the first cross-over frequency, each of the M second waveform-coded signals corresponding to a respective one of the M encoded channels; and interleaving the first waveform-coded signal with one of the M upmix signals such that an interleaved version of said one of the M upmix signals is obtained, wherein the interleaving comprises adding the first waveform-coded signal with one of the M upmix signals or replacing one of the M upmix signals with the first waveform-coded signal in the subset of the frequencies above the first cross-over frequency corresponding to the spectral coefficients of the first waveform-coded signal; and combining the M second waveform-coded signals with the M upmix signals before the interleaving, after the interleaving, or in a combined step with the interleaving to generate an M-channel output signal. receiving N frequency extended downmix signals comprising spectral coefficients corresponding to frequencies between a first and second cross-over frequency, k y, k x, and above the second cross-over frequency k x, wherein k x > k y; generating M upmix signals comprising spectral coefficients corresponding to frequencies above the first cross-over frequency k y by parametrically upmixing the N downmix signals into M upmix signals, and wherein the M upmix signals do not comprise frequencies below the first cross-over frequency k y, each of the M upmix signals corresponding to a respective one of M encoded channels, wherein 1<N<M; receiving a first waveform-coded signal comprising spectral coefficients corresponding to a subset of frequencies above the first cross-over frequency k y; receiving M second waveform-coded signals comprising spectral coefficients corresponding to frequencies up to the first cross-over frequency, each of the M second waveform-coded signals corresponding to a respective one of the M encoded channels; and interleaving the first waveform-coded signal with one of the M upmix signals such that an interleaved version of said one of the M upmix signals is obtained, wherein the interleaving comprises adding the first waveform-coded signal with one of the M upmix signals or replacing one of the M upmix signals with the first waveform-coded signal in the subset of the frequencies above the first cross-over frequency corresponding to the spectral coefficients of the first waveform-coded signal; and combining the M second waveform-coded signals with the M upmix signals before the interleaving, after the interleaving, or in a combined step with the interleaving to generate an M-channel output signal.