This paper discusses selected aspects of the multichannel digital processing of audio signals in time and frequency domains using a fixed-point digital signal processor. Emphasis is given to special features of modern digital signal processors and their efficiency in implementing real-time algorithms for digital filtering and signal transformations. Using these new signal processor features, digital filtering tasks can be realized in real-time without reducing cycle time. The algorithms described were implemented and tested using an experimental hardware (the Polish audio card DynaBit Studio) and the TMS320C542 fixed-point processor.