fixed. Within the time frequency blocks, the bits can be transferred between frequency sub-bands. With respect to Figure 1 an example apparatus and system for implementing embodiments of the application are shown. The system 100 is shown with an ‘analysis’ part 121 and a ‘synthesis’ part 13 1. The ‘analysis’ part 12 1 is the part from receiving the multi-channel loudspeaker signals up to an encoding of the metadata and downmix signal and the ‘synthesis’ part 13 1 is the part from a decoding of the encoded metadata and downmix signal to the presentation of the re-generated signal (for example in multi-channel loudspeaker form). The input to the system 100 and the ‘analysis’ part 12 1 is the multi-channel signals 102. In the following examples a microphone channel signal input is described, however any suitable input (or synthetic multi-channel) format may be implemented in other embodiments. For example in some embodiments the spatial analyser and the spatial analysis may be implemented external to the encoder. For example in some embodiments the spatial metadata associated with the audio signals may be a provided to an encoder as a separate bit-stream. In some embodiments the spatial metadata may be provided as a set of spatial (direction) index values. The multi-channel signals are passed to a downmixer 103 and to an analysis processor 105. In some embodiments the downmixer 103 is configured to receive the multi- channel signals and downmix the signals to a determined number of channels and output the downmix signals 104. For example the downmixer 103 may be configured to generate a 2 audio channel downmix of the multi-channel signals. The determined number of channels may be any suitable number of channels. In some embodiments the downmixer 103 is optional and the multi-channel signals are passed unprocessed to an encoder 107 in the same manner as the downmix signal are in this example. In some embodiments the analysis processor 105 is also configured to receive the multi-channel signals and analyse the signals to produce metadata 106 associated with the multi-channel signals and thus associated with the downmix