Apparatus for encoding a multi-channel signal comprising at least two channels, wherein the multi-channel signal is a multi-channel audio or speech signal, comprising: a time-spectral converter configured for converting sequences of blocks of sampling values of the at least two channels into a frequency domain representation having sequences of blocks of spectral values for the at least two channels; a multi-channel processor configured for applying a joint multi-channel processing to the sequences of blocks of spectral values to obtain at least one result sequence of blocks of spectral values comprising information related to the at least two channels; a spectral-time converter configured for converting the result sequence of blocks of spectral values into a time domain representation comprising an output sequence of blocks of sampling values; and a core encoder configured for encoding the output sequence of blocks of sampling values to obtain an encoded multi-channel signal, wherein the core encoder is configured to operate in accordance with a first frame control to provide a sequence of frames, wherein a frame is bounded by a start frame border and an end frame border, and characterised in that the time-spectral converter or the spectral-time converter are configured to operate in accordance with a second frame control being synchronized to the first frame control, wherein the start frame border or the end frame border of each frame of the sequence of frames is in a predetermined relation to a start instant or an end instant of an overlapping portion of a window used by the time-spectral converter for each block of the sequence of blocks of sampling values or used by the spectral-time converter for each block of the output sequence of blocks of sampling values. a time-spectral converter configured for converting sequences of blocks of sampling values of the at least two channels into a frequency domain representation having sequences of blocks of spectral values for the at least two channels; a multi-channel processor configured for applying a joint multi-channel processing to the sequences of blocks of spectral values to obtain at least one result sequence of blocks of spectral values comprising information related to the at least two channels; a spectral-time converter configured for converting the result sequence of blocks of spectral values into a time domain representation comprising an output sequence of blocks of sampling values; and a core encoder configured for encoding the output sequence of blocks of sampling values to obtain an encoded multi-channel signal, wherein the core encoder is configured to operate in accordance with a first frame control to provide a sequence of frames, wherein a frame is bounded by a start frame border and an end frame border, and characterised in that the time-spectral converter or the spectral-time converter are configured to operate in accordance with a second frame control being synchronized to the first frame control, wherein the start frame border or the end frame border of each frame of the sequence of frames is in a predetermined relation to a start instant or an end instant of an overlapping portion of a window used by the time-spectral converter for each block of the sequence of blocks of sampling values or used by the spectral-time converter for each block of the output sequence of blocks of sampling values.