Turn Your Raspberry Pi Fleet Into a Bluetooth and Wifi Multi Room Audio System

This tutorial will show you how to setup your Raspberry Pis in order to build a multi room audio system working over the wifi network. The audio will be shared to this system through bluetooth

The best Rapsberry Pi to be used is the Raspberry Pi 3 Model A+, running Raspberry Pi OS Lite. This document is using the default pi user as an example.

Initial setup of Raspberry Pi OS Lite

Flash the OS to a SD card with balenaEtcher. In order to run it headless (i.e. without any screen), place in the boot partition a file called wpa_supplicant.conf with the following data:

country=FR
ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1

network={
    ssid="WIFI_SSID"
    scan_ssid=1
    psk="WIFI_PASSWORD"
}

In addition to that, place a empty file called ssh in the very same partition, in order to enable ssh access

After the first boot, you will be able to access you raspberry pi via ssh:

ssh pi@raspberrypi

The default password is raspberry

Setting up a Snapcast server

The snapcast server will be both the snapcast central server and a client to have it playing music as well. It will retreive its audio source from bluetooth like so:

Device > Bluetooth > Pulseaudio > Alsa Loopback sink > Alsa Loopback source > Snapcast server > Network > {snapcast clients}

network
├── > Snapcast Client 1 (the one ran on the same device than the server) > Alsa Headphone sink > Jack
├── > Snapcast Client 2 > Alsa Headphone sink > Jack
├── > Snapcast Client 3 > Alsa Headphone sink > Jack
└── > ...

Dependancies

sudo apt update
sudo apt install pulseaudio pulseaudio-module-bluetooth

Get the armhf versions of the snapcast server and clients and install them. For example, for the version 0.26.0 of snapcast:

wget https://github.com/badaix/snapcast/releases/download/v0.26.0/snapclient_0.26.0-1_armhf.deb
wget https://github.com/badaix/snapcast/releases/download/v0.26.0/snapserver_0.26.0-1_armhf.deb
sudo dpkg -i snapclient_0.26.0-1_armhf.deb
sudo dpkg -i snapserver_0.26.0-1_armhf.deb
sudo apt --fix-broken install

General configuration

Edit /etc/hostname and /etc/hosts to replace raspberrypi by something unique, let's say for example node_titulebolide. It will set the DNS name of the server as well as its bluetooth device name.

Snapcast configurations

Setup the alsa loopback and make it visible to pulseaudio:

• Add the line snd-aloop at the end of /etc/modules
• Add the lines in /etc/pulse/default.pa
  • load-module module-alsa-sink device=hw:0,0
  • set-default-sink alsa_output.hw_0_0
• Change the very last line of /etc/default/snapclient to:
  • SNAPCLIENT_OPTS="--host 127.0.0.1 -s Headphones"
• Edit the file /etc/snapserver.conf and change the source parameter to:
  • source = alsa://?name=Snapserver&device=hw:0,1,0
• Change the bluetooth device Class of Service:
  • sudo hciconfig hci0 class 0x240408

Setup pulseaudio service by creating and edition the file /etc/systemd/system/pulseaudio.service and writing:

[Unit]
Description=PulseAudio Deamon

[Install]
WantedBy=multi-user.target

[Service]
Type=simple
User=pi
Group=pi
ExecStart=/usr/bin/pulseaudio --realtime --exit-idle-time=-1

Setup the service to be started on boot:

sudo systemctl daemon-reload
sudo systemctl enable pulseaudio

Reboot.

Bluetooth connection

Open the bluetooth connection manager by running:

bluetoothctl

The bluetoothctl environment will open. Paste:

discoverable yes
pairable yes

Now take the device you want to pair and search for your rasperry pi and pair it, confirming the codes and connections both on the device and on the raspberry pi.

Still on the bluetoothctl environment, once the device is connected:

trust
exit

This should be good to go.

Setting up a Snapcast client

Get the armhf versions of the snapcast client and install it. For example, for the version 0.26.0 of snapcast:

wget https://github.com/badaix/snapcast/releases/download/v0.26.0/snapclient_0.26.0-1_armhf.deb
sudo dpkg -i snapclient_0.26.0-1_armhf.deb
sudo apt --fix-broken install

Afterwards you will just have to edit the file /etc/default/snapclient to: SNAPCLIENT_OPTS="--host <HOSTNAME>.lan -s Headphones". In our example <HOSTNAME> is node_titulebolide. <HOSTNAME>.lan can be replaced by the server's IP if it is static.

Debugging the server

The routing of the sound can be sometime quite complicated, it can be debugged with:

• aplay -l
• pactl list
• pactl info
• journalctl -f -u snapclient
• journalctl -f -u snapserver