Mixer Inputs and Outputs
DJ Mixers found in nightclubs have to adapt to perform with all sorts of DJ’s over the course of their working lifetime. Unlike DJ controllers that are designed just be used with a laptop the majority of the time, a stand alone mixer has to be able to accommodate a range of devices and DJs. It’s for this reason that the back of a professional mixer can look a little daunting to the first time user.
Line – Line Level inputs are handled by unbalanced RCA cables. These are used for plugging in CD players, DJ Controllers, iPods ect.
Phono – Phono is specifically used for turntables as it boosts the levels and apples EQ by running the signal through a pre-amp. Do not attempt to plug anything other than turntables into these connections, despite the face they are also unbalanced RCA’s.
Digital – Rather than carrying the electrical signal of the sound, digital connections carry data. These 1’s and 0’s carry the data of the sound you’re playing to be converted into sound elsewhere. These are a handy way of using a single cable to carry both left and right channels of audio over a single RCA connection. This will need a compatible mixer and player however and isn’t commonly used even when available with people preferring the sound quality of Line Level connections.
Microphone – Microphone inputs come in a few shapes. Usually a TRS connection carrying a balanced mono signal, this 1/4” jack is used for Microphones only. The signal, much like turntables is run through a pre-amp and therefor you can not plug anything else such as a guitar into the mixer as it won’t sound correct. Some mixers carry a XLR input for the microphone or a combo socket which is an XLR with a TRS jack in the centre to give DJ’s the choice.
USB – Used as an input and also an output, this digital connection allows users to connect the mixer to a computer and use its internal sound card. This means the computer can use the channels of the mixer for DJ software but also capture the sound of the outputs such as Master Out and Record Out.
This allows computers to record the DJ’s performances should they need. Some high end mixers now feature two USB ports for back to back laptop performances or one laptop recording the others set. The USB port can also transfer MIDI data to allow the mapping of the mixers buttons to functions within performance software and the send and return of accurate BPM information to the mixers effects unit.
Booth – Usually connected via balanced mono TRS or XLR connections, these connections allow you to connect a set of speakers that reside inside the DJ booth. These can then be controlled independently of the master speakers so the DJ can choose when to hear what the crowd hears more clearly without affecting the dace floors volume.
Master Out – Most professional mixers will feature two master outs, one balanced and one unbalanced. In professional settings it’s always better to connect via balanced XLR’s however the unbalanced RCA connection is usually found too incase you need to plug into cheaper speakers or another mixing desk.
Some mixers will also feature a digital master out, however it’s rare you would use this connection as it requires another mixing desk before reaching the amplifiers and speakers. Although not very common, some DJ mixers will offer a digital master out, connected via a single RCA cable. This can be a useful connection when daisy chaining mixers together.
MIDI Out – Another rare connection for your typical club DJ, the midi port allows other MIDI instruments to be connected to share the same midi clock. This allows external devices such as drum machines to stay perfectly in time with the midi clock of the mixer, which is usually set by the on board effects unit.
Headphones – The first port most DJ’s will come to on a DJ mixer, the headphones are found on unbalanced stereo TRS ports. Most mixers will have 1/4’’ jack as it’s more durable than the 1/8” that’s found on a mobile phone/iPod. Although some newer devices carry both. This port should need little explanation.
Send/Return Loop – Usually 4 TRS balanced jack connections grouped together on a mixer, the send return is used for connecting external sound effect units to a DJ mixer. Sending a left and right balanced sound to the external device over the two send channels, the effects unit such as a Pioneer RMX 1000 or Korg Chaos Pad then processes the sound, adds an effect and send it back. This sound is sent back over two further jack cables that connect back to the Return TRS ports on the mixer.
Some more technical mixers such as the Allen & Heath Xone 96 and PLAYdifferently MODEL1 feature more than one send and return loop. In more modern Pioneer mixers, the ability to perform a send/return has been enabled via a USB connection for software based effects units. Once connected you will need to activate the send return loop via either the mixers onboard effects unit or via the dedicated volume controls. Check the mixers user manual before your gig if you are unsure on how to fully use this feature.
Grounding Posts – Key to using vinyl in your mix, the grounding posts are two metal threads with thumb screws that you should connect your turntables grounding wire to. Without grounding your turntables, your signal will suffer unwanted distortion and noise. It’s always preferable to ground your turntables to devices plugged into the same power sockets as them, making the mixer usually an ideal choice. Note these can be called Signal Ground on some mixers.
Link Port – Depending on your mixer you may have one or several of these ports. Used as a digital connection, there’s a whole host of features that these ports enable depending on the brand of mixer and decks. Mainly used to connect the mixer to the decks to enable on air display and accurate BPM and Quantise options on the mixers effects unit.
These connections can also be used to control lighting software and much more. If the mixer has a a few link ports it may be being used as a hub to connect other players together. If this is the case be aware that using link features such as playing from another players USB/SD may be affected if you turn the mixer off or knock the cables. Otherwise these aren’t used to control the internal sound card like a USB connection and as such aren’t a connection to worry too much about.