Inputs & Outputs on an audio interface – A complete List!

Inputs & Outputs on an audio interface

In this article, we have a closer look at various inputs & outputs present on an audio interface.

Audio Interface: An audio interface is a medium to record crystal clear and studio-grade sound quality in simple words. It is similar to a sound card but has better converters and mic preamps that retain audio dynamics precisely. For recording purposes, there are different types of inputs and outputs on an audio interface.

Getting numerous inputs and outputs is exciting only if you know how to use them. A lot of producers struggle with the utilities that various inputs and outputs provide in an interface. Some are easy to understand, while others need a proper explanation.

For this purpose, I have listed down an entire list of inputs and outputs that you may see in an interface. A beginner-level interface will have basic I/Os, while a high-end audio interface will give you all the ports.

[Also check: Top 15 things to consider before buying an audio interface]

Different Types of Inputs on an Audio Interface

In this section of the article, we are having a look at various types on inputs present in an audio interface. In addition, we will also discuss their utility.

Also, you do not have to buy a super expensive audio interfaces to get all the input and output ports on an audio interface.

Some of the best audio interfaces under $500 are going to have most of the inputs and outputs on an audio interface, if not all of them.

1) Microphone level inputs

Inputs & Outputs on an audio interface - MIC LEVEL INPUT

The first standard input in most of the audio interfaces is the Mic level input.

This type of input connects with microphones mostly to record vocals or instruments. The microphones can either be condenser or dynamic depending on whether the interface has phantom power or not. A +48V phantom power ensures that the mic input is capable of pairing with both types of mics.

The mic level input has three components attached to it. These are:

  • Mic Preamps,
  • A/D converters,
  • Amplifiers.

Make sure you have XLR cables in case you want to record microphones through an audio interface.

All these components ensure that:

  • Sound quality remains as high as possible,
  • No unwanted noise is induced or captured,
  • Each bit of the sound wave is recorded.

[Also check: Audio interface setup diagrams to connect and pair guitars, mixers, MIDI, mics, monitors and more!]

2) Line level Inputs

Inputs & Outputs on an audio interface - LINE LEVEL INPUT

Line-level inputs are the type of inputs used to pair with line-level instruments such as a keyboard where no amplification is required. Devices like the keyboard have an inbuilt amplifier which eliminates the need of tweaking the incoming audio signal.

In addition, these inputs ensure that:

  • Audio is recorded in the highest quality possible.

Here, the audio signal is very strong as compared to that of a mic or a guitar. Hence, the need for amplification is eliminated.

So, if you see an instrument with an inbuilt amplifier, connect it to the line-level input.

Lastly, the line level inputs need basic 1/4″ TRS cables to connect to the line level instrument.

For example, Synths, keyboards, drum machines.

[Also check: Here are the Best Audio Interfaces For Home Studio that professionals use!]

3) Mic / Line combo Inputs

Inputs & Outputs on an audio interface - MIC LINE COMBO

Most of the inputs in the Budget audio interface are Mic/line combo inputs.

Such inputs can connect to both line level and mic levels inputs such as mics, keyboards, or mixers.

Both types of cables, i.e., XLR or TRS, can be easily inserted in such ports but only cable one at a time.

4) “High Z” / High impedance / Instrument inputs

High Z inputs are also known as high impedance inputs and are used to connect and record basses or guitars.

Having such a type of input arises because the guitar that connects to the interface needs impedance matching. Otherwise, the audio quality will suffer.

You can connect Hi-Z instruments to such inputs using a 1/4″ TRS cable.

[Also check: Top audio interfaces that are great for recording guitars also! ]

5) MIDI input

MIDI instruments

The MIDI port contains both inputs & outputs on audio interface. Let’s discuss the input port here.

Next comes the MIDI input, which works in sync with MIDI output. As long as both the MIDI ports, i.e., input and output, are connected to the interface, the MIDI instrument will work perfectly.

The MIDI inputs transfers an audio signal from the MIDI instrument to the audio interface and then from the audio interface to either studio monitors or the headphones.

Cables required: 5-Pin MIDI cable.

EXAMPLE: MIDI Samplers, MIDI Synths, or MIDI keyboards.

[Also check: Best portable audio interfaces for touring artists]


ADAT inputs

What if you want to increase the capacity of your audio interface from 8 inputs to 16 inputs?

Or say you want to join two audio interfaces together to have more inputs & outputs at your disposal.

On a ton of audio interfaces, there is an input that goes by the name of ADAT. It allows you to join two audio interfaces to increase the input and output capacity of an audio interface.

The ADAT input on the interface connects to the ADAT output on the second interface using ADAT cables.

Why is ADAT helpful?

The moment you want to record a drummer, the ADAT input can come in very handy. As a drummer session requires more audio channels, connecting two audio interfaces becomes a necessity. This joining of two interfaces and increasing your interface capacity to more input channels is done by ADAT.


SPDIF inputs and outputs on an audio interface

The SPDIF input of an audio interface connects to the SPDIF output of different external studio gear that you might own.

Basically, it helps the audio to be send from audio interface to a studio gear that also has an SPDIF port. The reason for sending audio signal from interface to a different gear is sound processing.

Suppose, you have a compressor and want to process a drum loop. For this, you’ll need to set adequate channel in the DAW which has the compressor connected to it. This work cannot be done by regular line level outputs due to variance in many factors like sound quality. Therefore, the need of SPDIF arises.

Different Types of Outputs on an Audio Interface

Let’s move to the next part in our article that discusses inputs & outputs on audio interface.

As we have discussed the input section, we are all set to have a look at outputs of an audio interface.

1) Main / Line level outputs

Inputs & Outputs on an audio interface

Each audio interface has at least two outputs. Mostly, you’ll find these on the back of the interface labelled as Line outputs or Main outputs. In addition, many audio interfaces have L (for left) and R(for right) written on them.

These two line-level output ports connect to the input ports located on the external speakers or Studio Monitors.

Audio interface output cables:

The Studio monitors can be easily paired with the interface using the line-level output and 1/4″ TRS cables. Make sure to order/buy them in advance.

[Also check: Do you need an audio interface to connect to studio monitors?]

As you upgrade to a better audio interface, the number of output options will increase as well. Having more outputs is a convenient way to send the audio signal for different purposes.

You can connect the main outputs to studio monitors and use additional outputs for:

  • Separate channel monitoring,
  • connect to a different type of studio gear like an FX rack,
  • add a new set of Studio monitors,
  • Mix your music on separate external speakers,
  • And many more!

Once you get more studio gear, you’ll realize that having an additional set of outputs is essential to advance and increase your studio capabilities.

2) Headphone outputs

The next category of outputs that all the interface have is headphone outputs.

Many professional or studio grade audio interface may have as many as four headphone outputs. But, basic budget audio interface around $500 will have atleast two headphone outputs.

The direct monitoring feature and the number of artists you can record simultaneously is dependent upon headphone outputs.

Multiple headphone outputs become important when you want to co-produce with, say, at least one artist. This way you can govern the type of the audio mix that an artist will get.

For example, you can set a highly processed audio mix for a guitarist. On the other hand, setting a highly processed signal for a signal may not work. So, you add some reverb, stereo width and take down some tracks when the singer is just laying the starting ideas.

All in all, more headphone outs mean more artists can have a separate mix of the audio signal which makes it easier for them to layer their part on top of the track.

3) MIDI output

inputs & outputs on audio interface

The MIDI input of the audio interface connects to the MIDI output of the MIDI instrument.

The MIDI instruments are a special type on an instrument that uses the MIDI capability to retain audio in MIDI information like how hard a note was pressed, engaged duration of a note, type of note played.

MIDI instruments are of various types like keyboards, samplers or synths. All these instruments have a MIDI port on the back panel with a MIDI input and a MIDI output.

As we talked about earlier, both the MIDI input and MIDI output work together. If one disconnects, the MIDI instrument will shut down. This is because the signal flow from the interface to MIDI or from MIDI to the interface is disconnected.

Also, keep in mind that if your MIDI instrument is not working, a common cause is that pin(s) of the cables may have been damaged.

4) Word Clock

If you have an engineering background, no one will understand the work clock better than you. In electronics, a clock is used for the synchronization of various systems. There are two main reasons for making devices work in synchronization:

  1. No data loss,
  2. No time lag.

Similarly, in the audio interface, the purpose of the word clock is to make various types of studio gears work in sync with each other. As soon as you connect the output of the word clock to studio gear, the audio interface works as a master and the other pieces of equipment as a slave.

It means that studio gear will work in accordance and compliance with an interface.

How will it benefit you?

Firstly, the signal flow will become smoother, making you frustrate less over why the audio is playing after 10 seconds.

Secondly, using the word clock will make sure that no audio information is lost over transmission.


Our sole focus was on understanding the input capacity provided by an ADAT input port in the ADAT input section.

But, in some audio interfaces, ADAT comes in the form of an input and an output. The input port works precisely the same as we discussed in the earlier section. The connections also remain the same.

A new port that we can see is the ADAT output port.

The ADAT output port is used to make things even more aligned, meaning that there will be better sync and fewer disruptions when the two audio interfaces are connected. Think of it as “closing the deal“.


You also have to set the clock, which forms one of the audio interfaces as master and the other as slave. The master-slave topology ensures that the interfaces complement each other’s work by know sample rates, logical time etc.


In the SPDIF Input section of this article, we saw that an audio signal is sent from the audio interface to SPDIF for additional sound processing. But, if you have not connected the SPDIF output port of the external gear to the interface, you’ll not be able to hear any sound.

So make sure that you connect the SPDIF output of the gear to the SPDIF input of the interface using proper cables.

This connection will send the processed signal from external processing gear like the compressor back to the audio interface.


The list mentioned above provides you with a complete list of inputs & outputs on an audio interface.

However, a thing to note is that you may not get each input or output port on a budget audio interface. As the cost increases, you’ll get to see more inputs & outputs on audio interface that we just discussed.

Still, a portable audio interface will provide you with all the standard options to connect and record most of your instruments.

On the other hand, a high-end professional audio interface will give you all classic ports to pair all your studio equipment and other audio interfaces too. The only downside here is the portability.

All in all, look for an interface that is portable and has enough ports to pair most of the studio gear. 

Be the first to comment

Leave a Reply

Your email address will not be published.