How to Connect a Mixer to an Audio Interface


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If you are interested in high-quality home music recording, chances are you have looked into a sound mixer and an audio interface to take your digital recording to the next level. Sound mixers (also called soundboards or audio mixers) let you control the volume and effects of each microphone or instrument input separately. Audio interfaces translate the analog sound from the mixer into digital computer signals.

How do you connect a sound mixer to an audio interface? Plug the audio output from the sound mixer into the audio input on the audio interface. You can use a quarter-inch cable, RCA cable, or XLR cable to make the connection. Check the inputs and outputs of your equipment to see which connections you have. If the devices have different types of cable ports, adaptor cables are also available.

It may sound as simple as plugging in a cable, but as you probably already know, it isn’t that simple. Continue reading for all the information you’ll need to set up your mixer.


Selecting the Best Cable to Connect a Mixer to an Audio Interface


Many devices have multiple input and output ports, allowing you to choose between cable types when connecting the mixer to the interface. Which type of cable is best?


XLRLess noise from interference over long runs Cost

“Balanced” cable signal only benefits if all components carry a balanced signal
RCALow cost

Compatible with older analog equipment
May pick up interference or noise over long runs
1/4 InchLow cost

May pick up interference or noise over long runs

If either of your audio components has only one audio jack type available to connect, you should choose the cable that fits, hook your system up, and start recording. However, if your components both have multiple jack types, you need to give the decision a little more thought.

Once you have selected the right cable, all you need to do is plug the audio output from the sound mixer into the audio input on the audio interface.


Parts of the System


The mixer board has always been the heart of a recording studio. All the microphones and instruments are plugged into the mixer board. Each input has its own channel, and you can control the volume and effects on each instrument separately. Once upon a time, the output from the mixer board went straight to master tapes, which were used to create the recordings for sale. That’s not the case anymore.

All the final mixing is now done with a computer. To get your mixer board output to the computer, you need another piece: the audio interface. The audio interface turns the analog signals from the mixer board into digital streams for that the computer can read. Having a good connection between the mixer board and the audio interface is vital for good recordings.

There are four links in the chain needed for a home recording studio:

  • Input from microphones and instruments. The connection from inputs to the mixer board depends on the equipment. Most microphones use XLR cables. Electric guitars and basses use ¼ inch cable. Synthesizers and other digital instruments use MIDI cables.
  • Mixer board. The mixer board can connect to the audio interface with ¼ inch cable, RCA cable, or XLR cable.
  • Audio interface. The audio interface connects to the computer with firewire or USB cables.
  • Computer. The computer is the final link in the chain. The digital signals are saved, mixed, and played back on the computer. The final product of your home recording studio is audio files that you can distribute on the internet or play back at home.

The connections between inputs and mixer board, and between audio interface and computer, are dictated by the requirements of the equipment. The only place you have a choice of cable type is for the connection between the mixer board and the audio interface. Which cable is best for that connection? To decide, it helps to understand a little about how different cables work.


Balanced vs. Unbalanced Cables


Audio cables are classified as “unbalanced” or “balanced” based on the way the signal is carried by the cable. Both kinds of cable have advantages and disadvantages. If your equipment allows you a choice, pick the cable connection based on which best fits your needs.


Balanced Cables


XLR cables are considered balanced. These cables have two wires carrying the signal. The cable reverses the signal in one of the wires at the beginning, then flips it again at the other end. Any distortion in the signal is canceled out and the output sounds just like it did going into the cable. Interference from outside signals is eliminated from the final sound.

Balanced signals are good for very long runs of wire. XLR cables are common in professional studios and concert venues where the cables are tens or even hundreds of feet long. These cables keep the sound true and minimize interference in the signal during transmission.


Unbalanced Cables


RCA and ¼ inch cables are considered unbalanced. That is, they have one wire carrying a single copy of the signal (in this case, from the mixer to the audio interface). If there is any kind of interference along the length of the wire, the sound is distorted and the quality suffers. Unbalanced cables should be limited to runs of ten feet or less. Over short runs, there is no distortion in unbalanced cables.

The advantages of balanced cables don’t usually come into play in home recording studios. The distance between the sound mixer and the audio interface in a home studio is usually just a few inches, rather than many feet. The signal loss and distortion in unbalance cables of this length is usually zero, so there isn’t a need for expensive XLR cables.

Sometimes, you don’t have a choice about which type of cable to use. Older analog equipment may not have XLR ports, requiring the use of unbalanced quarter-inch or RCA connectors. If you are setting up a home music studio to try to recreate the sounds of pre-digital recording studios, unbalanced cables may be the only choice to make older equipment work.


Which Cable Sounds Best?


Every recording setup has its own quirks. Sometimes, the components combine in ways that don’t produce the sound you want. The “rules” about how to set up a system might not work for you. Don’t be afraid to experiment with your setup to get a sound you like.

If you can check out different setups, either by borrowing cables or buying both types, you should try recording using both balanced and unbalanced cables. The details of each recording setup are unique, and what works in one may not work in another. Make a few recordings with one cable type, then switch and make a few more. Listen to the two sets and decide which meets your expectations.


Audio Mixer with Interface


If you are just starting to check out home recording setups and haven’t invested in gear yet, there is another option:  the all-in-one sound mixer with a built-in computer interface. These sound boards combine the multi-channel audio mixing board with the digital interface. You plug microphones and instruments into the sound board, then plug the sound board straight into the computer’s USB port.

The all-in-one boards eliminate the difficulties of connecting a sound mixer to an audio interface. It removes the need to link the sound mixer with the audio interface. The all-in-one audio mixers cost a little more, but they simplify the installation and guarantee that everything works together.


Making the Connection


However you decide to connect your sound mixer to the audio interface—XLR, RCA, quarter inch, or even an all-in-one board—remember why you are setting up the system in the first place. Get your components plugged in, fire up your mikes, and get to recording. The most important connection of all is the one between the speaker and your ears.

Rob Wreglesworth

Rob has come to terms with the fact he will probably never be a famous rock star....but that hasn't stopped him from writing and recording music in his home studio. Rob has over 15 years experience of recording music at home.

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