Audio encoder (2") for encoding a multichannel signal , comprising: a downmixer for downmixing the multichannel signal to obtain a downmix signal ; a linear prediction domain core encoder for encoding the downmix signal to obtain an encoded downmix signal , wherein the downmix signal has a low band and a high band, wherein the linear prediction domain core encoder is configured to apply a bandwidth extension processing for parametrically encoding the high band; a filterbank for generating a spectral representation of the multichannel signal ; and a joint multichannel encoder configured to process the spectral representation comprising the low band and the high band of the multichannel signal to generate multichannel information , wherein the linear prediction domain core encoder further comprises a linear prediction domain decoder for decoding the encoded downmix signal to obtain an encoded and decoded downmix signal ; wherein the audio encoder (2") further comprises a multichannel residual coder for calculating an encoded multichannel residual signal using the encoded and decoded downmix signal , the encoded multichannel residual signal representing an error between a decoded multichannel representation obtained by using the multichannel information and the multichannel signal before the downmixing by the downmixer , and wherein the linear prediction domain decoder is configured to obtain, as the encoded and decoded downmix signal , only a low band signal representing the low band of the downmix signal , and wherein the encoded multichannel residual signal has only a band corresponding to the low band of the multichannel signal before the downmixing by the downmixer . a downmixer for downmixing the multichannel signal to obtain a downmix signal ; a linear prediction domain core encoder for encoding the downmix signal to obtain an encoded downmix signal , wherein the downmix signal has a low band and a high band, wherein the linear prediction domain core encoder is configured to apply a bandwidth extension processing for parametrically encoding the high band; a filterbank for generating a spectral representation of the multichannel signal ; and a joint multichannel encoder configured to process the spectral representation comprising the low band and the high band of the multichannel signal to generate multichannel information , wherein the linear prediction domain core encoder further comprises a linear prediction domain decoder for decoding the encoded downmix signal to obtain an encoded and decoded downmix signal ; wherein the audio encoder (2") further comprises a multichannel residual coder for calculating an encoded multichannel residual signal using the encoded and decoded downmix signal , the encoded multichannel residual signal representing an error between a decoded multichannel representation obtained by using the multichannel information and the multichannel signal before the downmixing by the downmixer , and wherein the linear prediction domain decoder is configured to obtain, as the encoded and decoded downmix signal , only a low band signal representing the low band of the downmix signal , and wherein the encoded multichannel residual signal has only a band corresponding to the low band of the multichannel signal before the downmixing by the downmixer . <EOS>