The development of Digital Signal Processing with low cost high-speed computer hardware and large hard disks has made the computer analysis of bioacoustical signals an everyday invaluable tool for ethological research. The latest versions of our real-time Digital Signal Processing Workstation (DSPWI meets most of the needs for sound recording and analysing. The system can deal with signals ranging from infrasounds to ultrasounds both in the lab and field. It is based on standard PC hardware and can be fully configured depending on the research needs. The software package includes analysis, recording and display tools, with real-time spectrogram and cepstrogram, spectral averaging, frequency tracking, event counting, scheduled recording, etc. Sound files and spectrograms can be saved to allow further processing with other standard software. A portable version can be easily moved across laboratories or used in field applications, for example those requiring real- time visualisation and recording of acoustic events. Depending on the installed sound acquisition devices, analogue I/O is possible in the audio frequency range and/or in the ultrasonic range up to 180kHz. Digital I/O is supported for direct transfer from DAT recorders to the PC. Real-time capabilities, typically available in much more expensive instruments are very useful in laboratory experiments to monitor the acoustic activities of the subjects (immediate correlation between observed behaviours and emitted/received signals) and to optimise the instrumental set-up (minimisation of noise, microphone placement).These facilities enable the immediate evaluation of experimental results instead of waiting for later analyses on the recordings, and they make it easier to analyse long periods. To date, the DSPW has been extensively used by many researchers to study sounds produced by fishes, birds, marine and terrestrial mammals and ultrasounds emitted by ants, moths and rodents. Examples will be shown on the poster and in the technical demonstration.