From DJWiki

In the 1960s and early 1970s, MDJs struggled to make do with whatever sound equipment they could piece together. Usually, this meant starting with a musical instrument’s amplifier or one from a hi-fi or stereo designed for “home” use. The unit would be customized for the task by changing connectors, adding cooling fans and making a few internal wiring modifications.

Many speaker systems were “home-brew” designs as well, utilizing geriatric components from old TV and radio sets, discarded record players and outdated guitar and organ speakers. Once a few functioning woofers and tweeters1 were gathered from the trash, they would be mounted in a variety of interesting arrays in anything from an old TV cabinet to a well-crafted plywood box.

An early subwoofer2 system (circa: 1966) was fabricated using a 12- or 15-inch speaker mounted face up in the bottom of a large plastic trash pail. Equipped with it’s own outboard amplifier, it could be placed anywhere at the site to reinforce the bottom end. It actually worked quite well, but keep in mind that, back then, anything that worked was considered to work well.

Today, professional equipment—like dual CD players, cassette decks, turntables, speaker systems, power amplifiers, wireless microphones and disco mixers (with and without digital samplers)—is readily available either by mail order or at numerous DJ specialty stores.

In Your System

Every Mobile DJ sound system is made up of four parts:

1. Music sources are the components designed to play back prerecorded music. The music sources DJs commonly use are CD players, Mini-disc players, tape decks, DAT and turntables.

2. The audio mixer allows the DJ to control the volume (or level) of several music sources as they are simultaneously “mixed down” to a single output.

3. The power amplifier takes the output of the mixer and boosts the volume to a level which is capable of filling the room with sound.

4. Speaker systems are made up of a number of individual speakers and components within a single cabinet. Their job is take the amplified signal from the amplifier and covert it back into sound we can hear. Normally, a DJ will use two speaker systems. In stereo operation, one receives the left signal from the amplifier, the other receives the right. In monaural (mono), both speaker systems receive an identical signal. For added bass, a single or pair of subwoofers, which reproduce just the lower frequencies, may be added.

Interacting With Your System

A good sound system is one that’s reliable and comfortable to operate. One thing all good DJs have in common is their ability to keep the music pumping continuously just like it was a single four- or five-hour song. Any pauses, holes or “dead air” during a DJ’s performance breaks the momentum and can clear the dancefloor.

In order to provide an uninterrupted music flow, each individual music track3 will overlap the previous. These overlaps, or moments of transition where one song is fading out while the beat of another is coming in, are called Segués (Seg-ways).

To make tight segués, the music must start at the precise moment the DJ wants it. CD players automatically “cue” to the beginning of the song. But what if the DJ wants the music to start at a point other than the beginning? By listening through the headphones, a DJ can audition a musical selection without disturbing the song currently playing through the speakers. This procedure, called Cueing (Q-ing), enables the DJ to locate precise musical starting points as well as matching beats between two selections.