The Basic Equipment

Sound systems consist of five basic groups of equipment. 

 1. At least two music playing sources. Since DJs must keep a continuous flow of music,
they use at least two music sources. These sources can be any equipment that plays
pre-recorded music. Today, one can choose from CD players, turntables, MiniDisc players,
cassette tape players, DAT decks, computers, digital DJ systems, or stand-alone MP3
players. Any combination of these will do for playing straight music, but performance
DJ setups are more picky. You can mix from one turntable to a CD player. You can even
mix from a computer to a cassette player. Using the second player allows you to mix in
another song before the initial song has ended, allowing for a continuous program
without spaces between the music. Most mobile and club DJs use two CD players, two
turntables or a combination of both to play their music. Many mobile jocks are now
utilizing new technology such as MiniDisc and MP3 players, which we’ll discuss later.

2. Mixers, also known as “preamplifiers.” Your music sources output a really weak electronic
signal that must be amplified and converted into a controllable line-level signal. Mixers
control the individual volumes of each music source and let you determine the output
level of each channel. 

 3. Amplifiers. The preamplified line-level signal is then electronically amplified so that
its resulting volume is strong enough to significantly overpower the room noise. The
amplified signal is sent over wires to remotely placed speakers that produce the sound
we hear.

 4. Speakers. Paper, plastic, or urethane cones are attached to a mounted coil of wire that is
vibrated by a magnet that produces an electronic vibration based on the signal that comes
directly from the amplifier. The coil moves the cone, the cone moves the air molecules
touching it, and those vibrating air molecules are sent all over the room hopefully ending
up in your eardrum.

 5. Other stuff. Microphones, headphones, booth monitors, cables, connectors, and other
stuff that make your DJ job possible, easier, and/or more fun.

 Let’s take a brief look at each component as they’d appear in a typical mobile or club DJ setup.