How to use an audio interface

This explains how to use an audio interface. Taking the Focusrite / Scarlett 2i2 as an example, we will introduce the connection method and settings.
* The flow is basically similar for all audio interfaces, but may differ depending on the product. Please also check the product manual and manufacturer information pages individually.

Connection method

Connection with PC

Connect the USB cable to your PC and audio interface. For Thunderbolt connection audio interface, connect the PC and audio interface in the same way.
* It may be necessary to install the driver in advance. For details, refer to "What is a driver?" below.

[Input] Connection with microphone

Audio interfaces with a microphone input have combo jacks and XLR jacks, and the microphone connects to them. XLR Canon cables can be used for the cable. Depending on the model, even with a dynamic microphone, if you do not connect with the XLR terminal, it will not pass through the microphone preamplifier and the volume may not be sufficient.

CLASSIC PRO / MIX050 Microphone Cable 5m XLR Cannon

[Input] Connection with musical instruments

Instruments such as guitars and synths can be connected to the combo jacks and phone jacks. As for the cable, you can use a normal phone connector musical instrument cable.

Since the guitar has high impedance (resistance), it is necessary to insert the phone jack into a jack that supports high impedance. It may also be described as "Hi-Z" or "Inst." When connecting a synth or rhythm machine, it will be at the line level, so connect it to the "Line" terminal. When inputting a synth etc. in stereo, you will need to connect 2 channels (stereo L / R).

[Output] Connection with speakers

For connection with speakers, connect the audio interface side to the output terminal below. There may be a LINE OUTPUTS notation as shown in the image, but the notation varies depending on the device such as OUTPUT and MAIN OUT.

The output terminal varies depending on the device. Even with the above phone jacks, they may be TRS (balanced) or TS (unbalanced). Check which specifications you have for your interface and monitor speakers.
The TRS (balanced) jack compatible cable has two black insulating rings as shown in image ①, and the TS (unbalanced) jack compatible cable has one insulating ring as shown in image ②.
* You can also exchange audio signals by using a TS cable for the TRS jack and a TRS cable for the TS jack.

Image ①
Image ②

Also, the input on the speaker side may be an XLR terminal. In that case, use a cable that has an XLR terminal on one end and a TRS phone jack on the other end, as shown below. There are also male / female XLR connectors, so check the specifications of your device and select the correct cable.

In this case, the following types of cables can be used

What is a driver?

A diver software is required to make the PC recognize the audio interface when connecting to a PC. So to speak, it is a bridge between a PC and an audio interface. Some models use the driver that comes standard with the PC, but many manufacturer provide a dedicated driver for the audio interface. The dedicated driver allows you to take full advantage of the performance of the audio interface and enable detailed settings that suit your environment. Some audio interfaces have a built-in mixer, and some features of the audio interface can be turned on / off using this driver software. Some multifunctional models allow you to manipulate the effects.
* The Scarlett 2i2 driver does not come with a built-in mixer.

Driver installation

The installation method differs depending on the model used, but it can be often downloaded from the manufacturer's site and installed. The Focusrite / Scarlett 2i2 is designed so that an icon is automatically displayed on the desktop when connected to a PC, and a driver installation dialog is launched from there. You can also download it manually from the official website.

Checking PC environment settings

After installing the driver, check the sound settings on your PC.

In Windows 10, [Start Menu]-> [Windows System Tools]-> [Control Panel]-> [Sound]
Select [Focusrite USB]

On Mac, [System Preferences] → [Sound]
Select [Scarlett 2i2] in [Output] and [Input]

Now let's check if the sound played from the PC is played from the audio interface. At the time of confirmation, anything that produces sound, such as music stored on the PC or videos such as YouTube, are OK.

Check your DAW environment settings

When the sound of the PC starts to flow from the audio interface, the next step is to set the sound of the DAW software to be output from the audio interface.
Scarlett 2i2 comes with Ableton Live lite, so I'll explain that here.

Click the [Audio] tab from [Preferences]
Select [Focusrite USB] as the audio interface device (select the appropriate audio interface for Mac)
Click the [IO] button at the bottom right of the screen
Select [1ch] for Audio From of the audio track
Set to [Auto] if Monitor is Off
If you press the REC preparation button, you can monitor 1ch.

Now you can monitor the input sound on your DAW software as well.

If there is no sound

If there is no sound, please check the following.

Is the cable connected correctly? Check if the audio flow such as output → input is correct.
If you have a condenser microphone connected, make sure that Phantom power (48V) is turned on.
Are the GAIN and volume of connected devices such as speakers, mixers, and audio interfaces set appropriately?
Is the driver installation complete?
Does the channel connected to the input match the channel set on the DAW side?
If there is no sound after checking the above, try restarting and reconnecting each device including the PC.