UPDATE: This now works out of the box in Ubuntu 20.04.

I recently bought a Focusrite Scarlett 2i2 (3rd Gen) audio interface and found that after plugging it in and booting the system I wasn’t able to get any audio output in Ubuntu 19.10. Below are the steps required to get this working.

Part 0 - Remove Existing Package

If you have previously installed qjackctl it’s important to uninstall it first.

$ sudo apt remove qjackctl

Part 1 - Add Required Repo

The kx.studio site has the instructions to add the repo but for ease of finding I’ll list the commands here.

NOTE: These commands may be outdated, check the website for version numbers.

1. Install the Required Dependencies

$ sudo apt install apt-transport-https gpgv

2. Remove Legacy Repos

$ sudo dpkg --purge kxstudio-repos-gcc5

3. Download Package File

$ wget https://launchpad.net/~kxstudio-debian/+archive/kxstudio/+files/kxstudio-repos_10.0.3_all.deb

4. Install

$ sudo dpkg -i kxstudio-repos_10.0.3_all.deb

Part 2 - Installing Cadence, Pulseaudio Module & Pavucontrol

1. Update Repos

Since we added a new repo we first need to update.

$ sudo apt update

2. Install Packages

$ sudo apt install cadence pulseaudio-module-jack pavucontrol

Part 3 - Open Cadence and Change Settings

1. Change ALSA Bridge in Cadence

Open Cadence, JACK Bridges should be located in the bottom right of the window. The ALSA audio bridge should be set to ALSA -> PulseAudio -> JACK.

2. Mute Audio in Pavucontrol

Open Pavucontrol and make sure all inputs and outputs are muted.

3. Force-Restart in Cadence

In the Cadence window, click Force-Restart. Hopefully this should then restart successfully.

With any luck your Scarlett interface should now be outputting to both your speakers and headphones (assuming you have both plugged in), try the hardware volume controls on the interface to check.