A DJ mixer is a type of audio mixing console used by disc jockeys (DJs) to control and manipulate multiple audio signals. Some DJs use the mixer to make seamless transitions from one song to another when they are playing records at a dance club. Hip hop DJs and turntablists use the DJ mixer to play record players like a musical instrument and create new sounds. DJs in the disco, house music, electronic dance music and other dance-oriented genres use the mixer to make smooth transitions between different sound recordings as they are playing. The sources are typically record turntables, compact cassettes, CDJs, or DJ software on a laptop. DJ mixers allow the DJ to use headphones to preview the next song before playing it to the audience. Most low- to mid-priced DJ mixers can only accommodate two turntables or CD players, but some mixers (such as the ones used in larger nightclubs) can accommodate up to four turntables or CD players. DJs and turntablists in hip hop music and nu metal use DJ mixers to create beats, loops and so-called scratching sound effects. Description DJ mixers are usually much smaller than other mixing consoles used in sound reinforcement systems and sound recording. Whereas a typical nightclub mixer will have 24 inputs and a professional recording studio's huge mixer may have 48, 72 or even 96 inputs, a typical DJ mixer may have only two to four inputs. The key feature that differentiates a DJ mixer from other types of larger audio mixers is the ability to redirect (cue) the sounds of a non- playing source to headphones, so the DJ can find the desired part of a song or track. A crossfader has the same engineering design as fader, in that it is a sliding control, but unlike faders, which are usually vertical, crossfaders are usually horizontal. To understand the function of a crossfader, one can think of the crossfader in three key positions. For a DJ mixer that has two sound sources connected, such as two record turntables, when the crossfader is in the far left position, the mixer will output only turntable A's music. When the crossfader is in the far right position, the mixer will output only turntable B's music. When the crossfader is at its midpoint (which is always marked with a horizontal line), the mixer will output a blend of turntable A's music and