May 1999

By the late 1990s, there was a noticeable trend towards seeking superior sound quality in professional digital audio processing, resulting in a shift from using 16-bit systems to those with 20-bit resolution. Sony was at the forefront of this shift, having already introduced a CD Mastering system. Sony in 1999 unveiled the Sony PCM-9000 Digital Master Disc Recorder, which employs an MO (Magneto-Optical) disc as its recording medium.