Digital signal processing
In 1990, MOTU added the ability to synchronise audio (digital audio) to Performer and released it as ""Digital" Performer," months after Opcode added this capability to Vision. Digital Performer was originally designed as a front-end to Digidesign's Audiomedia hard disk recording system, which later became Pro Tools. Digital Performer's specific appeal was its MIDI environment, which was fitted into the same transport system as the audio environment. This enabled users to record their MIDI instruments and mix the results with other live audio recorded in the studio (or vice versa). Personal computers of this time were too slow to handle high quality recording via their own CPU, so the addition of Digital signal processing co-processor cards was necessary to create a functioning audio recording studio. As the Mac's CPU became powerful enough to record the digitized audio directly to hard disk, the DSP cards were gradually rendered unnecessary. Foreseeing this, MOTU created its own Motu Audio System (MAS) which helped Digital Performer to tap the Macintosh's native power to record music directly to its own hard drive without the need for external co-processing and dedicated drives. By 2000, Digital Performer allowed users to record, mix, and master audio for commercial releases.