Applies to: All Focusrite audio interfaces
This is a guide to setting up your audio interface in Open Broadcaster Software (OBS) on a Mac. For instructions for Windows computers, please see the following article: How to set up your audio interface in OBS (Open Broadcaster Software) on Windows
OBS is a free program that allows you to stream audio and video to online platforms such as Facebook, Twitch, and Youtube.
To start, navigate to the OBS website and download the compatible version of OBS software for your system.
Setting the audio interface as the audio device
Once downloaded and installed, open the OBS application. If you're running macOS Mojave/Catalina then please ensure you grant OBS access to the "Microphone" as per the steps in this article, otherwise you'll get no audio.
With your audio interface connected please navigate to the Audio Mixer > Mix/Aux > Click the Settings button (small gear cog symbol) > Properties.
Select the audio interface you wish to use and select OK.
Once you have set your audio device in the properties you can then exit that window and navigate to the Advanced Audio Properties tab from the Settings menu.
Please make sure you have the mono setting ticked in the advanced audio properties. This will ensure that audio is heard by your audience on both sides of their headphones/speakers.
Once this is set then you can start to add different elements to your stream windows e.g. screen capture, text overlays, live video feeds etc.
From the Sources menu click the + symbol to add a new Source.
You can then add your incoming audio from your audio interface to the Sources so that your audience can hear you. Please select Audio Input Capture from the Source menu, select Add Existing and the Mic/Aux channel, and click OK.
After this, you can add other Sources if you wish. Display Capture allows you to show your audience what is happening on your screen which may be helpful when broadcasting things like tutorials. Video Capture Device allows your audience to view the feed from a webcam.
Once this is set up you will then be able to broadcast both your webcam, computer screen and incoming audio from your audio interface.
Sharing audio from your computer
There are a couple of ways you can route audio playing on your Mac into OBS and the method you choose largely depends on which interface you have and how many inputs you're looking to use.
Method 1. Use a third-party application such as iShowU Audio Capture. After installing this on High Sierra or above you will need to go to System Preferences > Security & Privacy and select "Allow". Then, open Finder > Applications > Utilities > Audio MIDI Setup - you should the application here if it has been installed correctly.
Click on the + symbol and then select Multi-Output Device.
Ensure iShowU Audio Capture and your audio interface are selected.
Go to System Preferences > Sound and ensure the Output is set to the Multi-Output Device
Navigate back to OBS and from the Sources menu click the + symbol to add a new Source. Create a new Source calling it computer audio.
Then select the iShowU Audio Capture as the audio device for this Source and click OK.
Method 2. Use a ¼ inch jack to jack cable to connect a line output on your audio interface directly to a line input on the interface. This method is better suited to our larger audio interfaces where you have spare outputs/inputs you can utilise. It will allow you to create separate mixes of audio for what you hear in your headphones/speakers and what the audience is hearing and is explained in the below articles.
Focusrite Interfaces that use Focusrite Control: How to create a Mix suitable for Video Calls, Conferencing and Lesson Calls/ for Scarlett 2nd/3rd Gen or Clarett
Focusrite interfaces that use Scarlett/Saffire Mix Control: How to create a Mix suitable for Video Calls, Conferencing and Lesson Calls/ for 1st Gen Scarlett or Saffire
Once you have set up OBS, you can then live stream directly to your chosen platform by going to Preferences > Stream and entering your Stream Key. An example of how to do this with Facebook Live can be found below.
Note Audio/Video Sync Issues
If you notice that your audio is not syncing up with your video, you may need to apply a sync offset to synchronize them in the Advanced Audio Properties. You can adjust the Sync Offset value in milliseconds. The exact value you set depends on how your computer is processing the audio and video, so you will have to experiment in order to find the right value.