there are several types of djs. a radio dj plays music files (like mp3) or recorded cds on a radio station and announces the names of the songs. a club dj plays music files or recorded cds over a pa system (an amplifier and loudspeakers) at a nightclub, rave, or disco. a hip hop dj uses turntables and vinyl records to do scratching and make music while other hip hop musicians do rapping (rhythmic type of singing). a reggae dj plays recordings of rhythm instruments and then rap on top of the prerecorded track with a microphone.