The Compact Cassette was originally intended for use in dictation machines. In this capacity, some later-model cassette-based dictation machines could also run the tape at half speed (15⁄16 in/s) as playback quality was not critical. The Compact Cassette soon became a popular medium for distributing prerecorded music—initially through The Philips Record Company (and subsidiary labels Mercury and Philips in the U.S.). As of 2009, one still finds cassettes used for a variety of purposes such as journalism, oral history, meeting and interview transcripts and so on. However, they are starting to give way to Compact Discs and more "compact" digital storage media.
The Compact Cassette quickly found use in the commercial music industry. One artifact found on some commercially produced music cassettes was a sequence of test tones, called SDR (Super Dynamic Range, also called XDR, or eXtended Dynamic Range) soundburst tones, at the beginning and end of the tape, heard in order of low frequency to high. These were used during SDR/XDR's duplication process to gauge the quality of the tape medium. Many consumers objected to these tones since they were not part of the recorded music