Getting 5.1 Surround Sound Working over HDMI ARC on Bazzite

Install the AC3 encoder plugin

Bazzite is an immutable OS, so software installs go through rpm-ostree rather than a standard package manager.

1. Open the Terminal.
2. Copy the command below, paste it into the Terminal, and press Enter.
3. Enter your password if prompted, then wait for the install to finish.
4. Reboot your PC — the plugin won't be available until you do.

sudo rpm-ostree install alsa-plugins-a52

Find your HDMI audio device

You need to find which card and device number Linux uses for your TV's HDMI output.

1. Open the Terminal.
2. Paste the command below and press Enter.
3. Read through the output and look for a line that mentions your TV — it'll usually show the manufacturer name (e.g. Samsung).
4. Note down the card number and device number from that line.

aplay -l

# Example output - yours will differ
card 1: HDMI [HDA ATI HDMI], device 10: HDMI 4 [SAMSUNG]

In this example: card 1, device 10. Keep these handy for the next step.

Release the HDMI device in PulseAudio Volume Control

This step uses a graphical app rather than the Terminal.

1. Open the Bazzite app store and install PulseAudio Volume Control (search for "pavucontrol").
2. Launch PulseAudio Volume Control from your app menu.
3. Click the Configuration tab.
4. Find the HDMI output connected to your TV and set it to Off or Disabled.

This releases the HDMI device so the custom AC3 setup can take control of it in the next steps.

Create the ALSA config

This creates a config file that tells ALSA how to encode audio as AC3 and route it to your HDMI output. You'll create the file in a text editor called nano, which opens inside the Terminal.

1. Open the Terminal.
2. Run the command below — this opens (or creates) the file ~/.asoundrc in nano. ~ means your home folder.

nano ~/.asoundrc

3. Copy the config block below. In nano, paste it with Ctrl+Shift+V (or right-click → Paste).
4. Find the line "hw:HDMI,10" and change it to use your numbers from Step 2. For example, if your card was 1 and device was 10, that line should read "hw:1,10".
5. Save the file: press Ctrl+O, then Enter to confirm the filename.
6. Exit nano: press Ctrl+X.

# Raw AC3 encoder
pcm.a52_raw {
    type      a52
    rate      48000
    bitrate   640
    channels  6
    format    S16_LE
    slavepcm  "hw:HDMI,10"  # your card and device here
}

# Safe wrapper - handles format conversion for apps
pcm.a52_safe {
    type plug
    slave.pcm "a52_raw"
    hint {
        show on
        description "TV (AC3 Surround)"
    }
}

The bitrate of 640kbit is the maximum for HDMI ARC.

Test the encoder

Before going further, confirm that audio is actually reaching your surround system.

1. Open the Terminal.
2. Paste the command below and press Enter.
3. You should hear test tones from each speaker. Press Ctrl+C to stop the test when you're done.

speaker-test -D a52_safe -c 6 -r 48000

If you don't hear anything, go back and check your card and device numbers in Step 2.

Create the PipeWire sink

1. Open the Terminal.
2. Run the first command below to create the folder (if it doesn't exist already).
3. Run the second command to open a new config file in nano.

mkdir -p ~/.config/pipewire/pipewire.conf.d
nano ~/.config/pipewire/pipewire.conf.d/ac3-sink.conf

4. Paste the config below into nano.
5. Save with Ctrl+O, then Enter.
6. Exit with Ctrl+X.

context.objects = [
  {
    factory = adapter
    args = {
      factory.name     = api.alsa.pcm.sink
      node.name        = TV_AC3
      node.description = "TV Surround 5.1"
      media.class      = Audio/Sink
      api.alsa.path    = a52_safe
      audio.channels   = 6
      audio.rate       = 48000
    }
  }
]

PipeWire will create the TV_AC3 sink automatically at startup from this config file.

Create a keepalive service (recommended)

Without this, your receiver may click or go silent during quiet moments because it thinks the audio stream has ended. This service plays inaudible silence into the sink to keep it active.

1. Open the Terminal.
2. Run the command below to create a new service file in nano.

nano ~/.config/systemd/user/ac3-keepalive.service

3. Paste the service config below into nano.
4. Save with Ctrl+O, then Enter.
5. Exit with Ctrl+X.
6. Back at the Terminal prompt, paste and run the two commands below one at a time (press Enter after each).

[Unit]
Description=Keep AC3 Output Alive with Silence
After=pipewire.service

[Service]
Type=simple
ExecStart=/usr/bin/paplay --raw --format=s16le --rate=48000 \
  --channels=2 --device=TV_AC3 \
  --property=media.role=background \
  --latency-msec=2000 /dev/zero
Restart=always
RestartSec=5

[Install]
WantedBy=default.target

systemctl --user daemon-reload
systemctl --user enable --now ac3-keepalive.service

Restart PipeWire and verify

1. Open the Terminal.
2. Paste and run the command below to restart the audio system.

systemctl --user restart pipewire pipewire-pulse wireplumber

3. Then paste and run this command to list available audio outputs:

pactl list short sinks

You should see TV_AC3 in the list. Set it as your default output in your audio settings, or select it per-application in PulseAudio Volume Control under the Playback tab.

Reboot and confirm

1. Reboot your PC using the normal shutdown/restart menu.
2. After logging back in, open the Terminal and run:

pactl list short sinks

TV_AC3 should still be in the list — PipeWire creates it automatically from the config file on every startup.