Structure

A typical modern DJ mixer generally has between two and six stereo channels for connecting and mixing audio sources. Each channel usually has a phono input with RIAA equalization for turntables and one or two line level inputs for sources such as CD players. Controls for individual channels are arranged in vertical columns (channel strips), starting with a switch or a knob selecting between the inputs. Below the input selector is a gain (or trim) control, used to match signal levels between channels. Next follows an equalizer section, used to fade parts of tracks in and out; a common basic technique is to kill the bass on one channel while mixing so the basslines of two tracks don't clash. A typical mixer features separate knobs for the low, mid and high frequency ranges. Some more controls may follow, such as a balance knob, built-in sound effects and aux-sends for external effects units. Below there's normally a cue switch sending the signal to the headphones, letting the DJ preview and beatmatch a track without sending it to the master output, but on some mixers there's a different way to select the cued source. The channel strip ends with a fader which sets the channel's signal volume in the final mix. The signal may pass through a crossfader. On simple mixers there are normally two channels assigned opposite ends of the crossfader, sometimes with a button to reverse the crossfader's direction. More advanced mixers have assignable crossfaders in which each channel can be assigned to either end of the crossfader or to bypass the crossfader entirely. Many scratch mixers have a crossfader curve control that effectively changes the distance the crossfader needs to travel to open the channel fully, letting to shorten it to a millimetre or two, which is useful for speedy scratching.