DSS (Digital Speech Standard) is a high-compression digital audio file format developed in 1994 by Grundig Business Systems at the University of Nuremberg, but officially released and specified in 1997 by the International Voice Association - a cooperative venture formed by Grundig Business Systems, Philips Electronics and the Olympus Corporation.

DSS files are designed specifically for compressing human speech and are used extensively in most digital voice recorders and dictation devices produced by the above-mentioned companies.

The major advantage of DSS files is their reduced file size. Compared to a WAV file of the same length for example, a DSS file would be only about 12% in size.

DSS is a proprietary format, meaning its specification is closed to third-party developers outside of the ones involved in the International Voice Association.

DSS files may contain metadata specifying how long the recording is or exactly when the recording was made. While DSS files can be easily played on PC or MAC with the freely-distributed Olympus DSS Player Lite, there are a number of free conversion tools available that allow converting DSS files to more common audio formats like MP3 or WAV.

One of the most popular free tools for that purpose is probably the Switch Sound File Converter Plus available on CNET.