A method of updating the state of a decoder that decodes a wide-band signal including a plurality of sub-band signals, including: receiving the plurality of sub-band signals; for each sub-band signal, storing portions of that sub-band signal in a respective buffer; responsive to determining that a portion of the wide-band signal is degraded, performing a packet loss concealment algorithm to determine wide-band replacement data for the degraded portion; selecting a portion of the sub-band signal stored in each buffer in dependence on the determined wide-band replacement data; and updating the state of the decoder using the selected portions.