Applies to:

• Scarlett 2nd Generation 6i6, 18i8, 18i20
• Clarett 4Pre and 8Pre USB
• Clarett+ 4Pre and 8Pre

This article will explain how to use multiple inputs on your interface in Voice over IP (VoIP) applications that will only accept incoming audio in mono (one-channel) or stereo (two-channel).

This can be useful for a number of different practices such as video lessons, conference calls, podcasting and even live-streaming, where you are using more than two inputs. Another advantage of using the steps in this article to set up your audio interface is you can have a separate mix of audio for what your VoIP audience hears. Compared to what you hear in your headphones/speakers, which is commonly referred to as a “Mix-minus”.

The steps below will work for most non-ASIO compatible VoIP applications that only accept audio from the first one or two inputs, such as Zoom, Skype, Teams, Discord and Teamspeak.

Requirements:

• Install the latest version of Focusrite Control from here.
• Ensure you have two ¼ inch jack to jack cable(s) available

Important: Before going through the method below, follow the steps in this article to enable access to different pairs of inputs in non-ASIO apps

In the below example, we are setting up a Scarlett 18i20 (2nd Gen) with a VoIP app that streams in stereo (two-channel) and we are using Line Outputs 3-4 as the mix output and Line Inputs 1-2 as the return input. However, the same theory applies if you wish to use different outputs and inputs on the device for the physical loopback or a different model interface, although you will need to alter the routing accordingly.

Method:

1. To start, open Focusrite Control and then go to File > Restore Factory Defaults. Your screen should look like the screenshot below.

2. Under the Output Routing section, choose an output to use. In this example, we are using Line Outputs 3-4.

3. In the grey box for Line Outputs 3-4 select Custom Mix in order to choose which audio you wish to send to this output (Note: Custom Mixes are disabled at 176.4 & 192kHz).

4. With Line Outputs 3-4 selected, ensure Analogue Input 1 and 2 are Muted within the Custom Mix. This will avoid a nasty feedback loop. In addition, Mute Software Playback 1-2 in this Custom Mix so the VoIP caller(s)/audience cannot hear themselves.

5. Add any other inputs you are using into the Custom Mix, by clicking on the + icon. Use Input 3 and onward for the XLR Mic Inputs or 1/4" Jack Line Inputs, and label them accordingly by clicking in the box above the fader.

6. Connect one end of a ¼ inch Jack to Jack cable to Line Output 3 and the other end to Line Input 1. Connect one end of the other ¼ inch Jack to Jack cable to Line Output 4 and the other end to Line Input 2. Use the gain dials to set the overall signal going into your VoIP application, ensuring the LED meter does not turn red at all to indicate the input clipping.

7. In your VoIP application, select your interface in the audio settings*, noting the application may display the input device as a Microphone and the output device as a Speaker.

*Please note, that you can select a different pair of inputs for the input device and use those for the physical loopback instead after following the steps here.

8. You can now use faders in the Custom Mix for Line Outputs 3-4 to mix the levels of the inputs while you are live on the call. For example, if one person or instrument is much louder than another, it can be useful to turn them down using the fader. In addition, by selecting the Output your headphones or speakers are connected to and assigning Custom Mix to them in Focusrite Control, you can adjust the volumes separately for what you are hearing, compared to what the VoIP audience is hearing.

For a guide on how to do this with Scarlett 3rd Gen interfaces, please see this article.