A method for encoding a plurality of input audio signals, wherein the method comprises: receiving the plurality of input audio signals and obtaining therefrom a plurality of baseband signals, a plurality of residual signals and a coupled-channel signal, wherein spectral components of a baseband signal represent spectral components of a respective input audio signal in a first set of frequency subbands and spectral components of an associated residual signal represent spectral components of the respective input audio signal in a second set of frequency subbands that are not represented by the baseband signal, and wherein spectral components of the coupled-channel signal represent a composite of spectral components of two or more of the input audio signals in a third set of frequency subbands; obtaining energy measures of at least some spectral components of each residual signal and the two or more input audio signals represented by the coupled-channel signal; obtaining energy measures of at least some spectral components of one or more synthesized signals to be generated during decoding, wherein the one or more synthesized signals have spectral components within the second set of frequency subbands and are generated by linear frequency translation of spectral components of the respective baseband signal, wherein some of the spectral components in the respective baseband signal are not translated, some of the spectral components in the respective baseband signal are translated once and some of the spectral components in the respective baseband signal are translated more than once by different amounts each time; calculating scale factors from square roots of ratios of the energy measures or ratios of square roots of the energy measures, wherein some of the scale factors are calculated from energy measures of at least some spectral components of the synthesized signals and other of the scale factors are calculated from energy measures of at least some spectral components of the coupled-channel signal; and assembling control information and signal information into an encoded signal, wherein the control information conveys a representation of the calculated scale factors and wherein the signal information represents the spectral components in the plurality of baseband signals and the coupled-channel signal. receiving the plurality of input audio signals and obtaining therefrom a plurality of baseband signals, a plurality of residual signals and a coupled-channel signal, wherein spectral components of a baseband signal represent spectral components of a respective input audio signal in a first set of frequency subbands and spectral components of an associated residual signal represent spectral components of the respective input audio signal in a second set of frequency subbands that are not represented by the baseband signal, and wherein spectral components of the coupled-channel signal represent a composite of spectral components of two or more of the input audio signals in a third set of frequency subbands; obtaining energy measures of at least some spectral components of each residual signal and the two or more input audio signals represented by the coupled-channel signal; obtaining energy measures of at least some spectral components of one or more synthesized signals to be generated during decoding, wherein the one or more synthesized signals have spectral components within the second set of frequency subbands and are generated by linear frequency translation of spectral components of the respective baseband signal, wherein some of the spectral components in the respective baseband signal are not translated, some of the spectral components in the respective baseband signal are translated once and some of the spectral components in the respective baseband signal are translated more than once by different amounts each time; calculating scale factors from square roots of ratios of the energy measures or ratios of square roots of the energy measures, wherein some of the scale factors are calculated from energy measures of at least some spectral components of the synthesized signals and other of the scale factors are calculated from energy measures of at least some spectral components of the coupled-channel signal; and assembling control information and signal information into an encoded signal, wherein the control information conveys a representation of the calculated scale factors and wherein the signal information represents the spectral components in the plurality of baseband signals and the coupled-channel signal.