rap rhythmic effect achieved by pulling a spinning record manually back and forth under the needle
This is the act of moving the needle back and forth along a groove in a record causing the sound contained within the groove to be played forwards and backwards at various speeds. A DJ will usually have one hand on the record and the other hand on the crossfader located on the mixer. By using the crossfader to cut the volume of the record in and out and moving the record back and forth at various speeds, the DJ can create many unique sounds. The type of sound sample used on the record also affects the sound of the scratch. For more information see the scratching section of this site.
Scratching is a DJ or turntablist technique originated by Grand Wizard Theodore, an early hip hop DJ from New York (AMG). Theodore developed scratching from DJ Grandmaster Flash, who describes scratching as, "nothing but the back-cueing that you hear in your ear before you push it [the recorded sound] out to the crowd." (Toop, 1991) Kool Herc was also an important early figure.