A method in an audio decoder, comprising: receiving an audio signal that comprises mixed audio content in a reference audio channel representation and metadata for speech enhancement of one or more audio channels in a Mid/Side, M/S, audio channel representation, the mixed audio content having a mix of speech content and non-speech audio content; transforming one or more portions of the mixed audio content that spread over two or more non-M/S channels in a plurality of audio channels of the reference audio channel representation into one or more portions of transformed mixed audio content in the M/S audio channel representation that spread over one or more M/S channels of the M/S audio channel representation, wherein the M/S audio channel representation comprises at least a mid-channel and a side-channel, wherein the mid-channel represents a weighted or non-weighted sum of two non-M/S channels of the reference audio channel representation, and wherein the side-channel represents a weighted or non-weighted difference of the same two non-M/S channels of the reference audio channel representation; performing one or more speech enhancement operations, based on the metadata for speech enhancement, on the one or more portions of transformed mixed audio content in the M/S audio channel representation to generate one or more portions of enhanced speech content in the M/S representation; combining the one or more portions of transformed mixed audio content in the M/S audio channel representation with the one or more portions of enhanced speech content in the M/S representation to generate one or more portions of speech enhanced mixed audio content in the M/S representation; wherein the method is performed by one or more computing devices. receiving an audio signal that comprises mixed audio content in a reference audio channel representation and metadata for speech enhancement of one or more audio channels in a Mid/Side, M/S, audio channel representation, the mixed audio content having a mix of speech content and non-speech audio content; transforming one or more portions of the mixed audio content that spread over two or more non-M/S channels in a plurality of audio channels of the reference audio channel representation into one or more portions of transformed mixed audio content in the M/S audio channel representation that spread over one or more M/S channels of the M/S audio channel representation, wherein the M/S audio channel representation comprises at least a mid-channel and a side-channel, wherein the mid-channel represents a weighted or non-weighted sum of two non-M/S channels of the reference audio channel representation, and wherein the side-channel represents a weighted or non-weighted difference of the same two non-M/S channels of the reference audio channel representation; performing one or more speech enhancement operations, based on the metadata for speech enhancement, on the one or more portions of transformed mixed audio content in the M/S audio channel representation to generate one or more portions of enhanced speech content in the M/S representation; combining the one or more portions of transformed mixed audio content in the M/S audio channel representation with the one or more portions of enhanced speech content in the M/S representation to generate one or more portions of speech enhanced mixed audio content in the M/S representation; wherein the method is performed by one or more computing devices.