Applies to: 

• Scarlett 2nd Generation 6i6, 18i8, 18i20
• Clarett 4Pre and 8Pre (All ranges)
• Scarlett 3rd Generation 4i4, 8i6, 18i8, 18i20

This article will explain how to use multiple inputs on your interface in Voice over IP (VoIP) applications that will only accept incoming audio from the first one or two audio inputs on an external audio interface. 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 that 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 VoIP applications that only accept audio from the first one or two inputs, such as Skype, Teams, Discord, Teamspeak, and Facebook Live.

*Please note that the below steps are not relevant with Zoom. On Mac computers, Zoom will be able to accept audio from all inputs on a device, but there is currently no way to choose which specific inputs you wish to use. Please refer to this article for Zoom set up on a Mac.

Requirements:

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

In the below example, we are setting up a Scarlett 18i20 (3rd Gen) with a VoIP app that only streams in mono and only accepts the first input of a device. However, the same theory applies regardless of whether you are using a VoIP app that accepts two channels of input audio, or you are using a different model interface, although you will likely 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 splitting Line Outputs 3-4 into two mono outputs and using Line Output 3.

3. In the grey box for Line Output 3 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 Output 3 selected, ensure Analogue Input 1 is 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 2 and onward for the XLR Mic Inputs or 1/4" Jack Line Inputs/Instrument 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. Use the gain dial 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.

*If you choose to use another Line Output instead, be sure to connect the cable to that output. In addition, if you are using a VoIP application that accepts two channels, be sure to leave the outputs as a stereo pair at step 2 and use two ¼ inch Jack to Jack cables, using Inputs 1 and 2 as the returns.

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

8. You can now use faders in the Custom Mix for Line Output 3 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.

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For a guide on how to do this with interfaces that use Scarlett Mix Control or Saffire Mix Control, please see this article.