Using multiple turntables, hip hop DJs play tracks of music to back up the MC. They also scratch records to create percussion sounds in hip hop. The equipment a DJ might use is varied. For instance, they often utilize headphones to listen to one recording while the other is still playing, and they also might have a 2-to-4 channel audio mixer to transition smoothly between recordings.
Beatbox is a vocal effect that creates the sounds of melodies, drums and rhythm. It is similar to the percussion effects of DJing, but without the electrical equipment. In the 1800s, barbershop quartets would harmonize their voices to make music. The use of voice effects were later used in blues, and today beatboxing thrives as an element of hip hop music. In some rap songs, it can even replace the DJ.
Sampling is a technique that uses a sample of a previous recording as if it's a musical instrument. Or the sample can be changed into a new sound altogether. This element of hip hop music began in the 1970s. It can be done with computer software, but also with vinyl records and tape loops. An example of a sample is when a break in a song is used in another song. Hip-hop artists such as the Beastie Boys and Dr. Dre have used sampling in their music.
Rapping is the art of lyrical speaking set to a beat. It is different than spoken word poetry in this regard. The flow of rap refers to its rhythm and rhymes, or its cadence. Central to the flow of rap is staying on the beat. There is a rhythmic pulse to rapping that stems from the MC stressing the syllables in time to a four-beat musical accompaniment.