In the mid-1970s, DJs began their careers in neighborhood parties, dance clubs, and public spaces. They recruited MCs (master of ceremonies) to keep the crowd energized and over time they would rhyme over the music. Kool Herc adapted "the technique of “mixing” between two turntables to create smooth transitions between records to the hip-hop aesthetic"(439). Grand Master Flash later refined the technique of mixing. Isolating breaks from songs allowed DJs to mix sections of it with other records. Grand Wizard Theodore was the DJ who invented scratching in 1978. DJs would “scratch” by moving a record back and forth, causing the needle to produce a scratching noise. This sound and technique is a symbol of old school hip-hop
