Signal processing parameter is settable separately for each of a plurality of channels (ch1-ch6). User designates a transfer source channel (e.g., ch1) and transfer destination channel (e.g., ch4) from among the plurality of channels, to thereby give a parameter transfer instruction. In response to the transfer instruction, the parameter setting of the transfer destination channel (ch4) and parameter settings of all channels (ch2-ch3) located intermediate between the transfer destination channel and the transfer source channel are sequentially shifted toward the transfer source channel (ch1), and the parameter setting of the transfer source channel (ch1) is transferred to the transfer destination channel (ch4). In this way, the parameter setting of the transfer source channel (ch1) is inserted into the transfer destination channel (ch4); the parameter settings of the other channels are sequentially shifted to respective adjoining channels in accordance with the parameter setting insertion.