MusicPi

A music playback device based on a Raspberry Pi 3

Features

• PulseAudio network sink (Device will just appear as a audio sink in PulseAudio)

Setup

Install Arch Linux ARM

Installation instructions

Create the required users

Pulseaudio requires a special user called pulse that is in the group audio. Create them with the following commapnds

useradd --home-dir /var/run/pulse pulse
gpasswd -a pulse audio

Install required packages:

Get root with su and password root, then install a system update and the required packages:

pacman -Syu alsa-firmware alsa-lib alsa-utils avahi pulseaudio pulseaudio-zeroconf

Adjust config files

/etc/pulse/system.pa

Append to the config file:

# Enable the native pulseaudio protocol, restrict to ip groups
load-module module-native-protocol-tcp auth-ip-acl=127.0.0.1;192.168.2.0/24;10.0.0.0/23

# Publish the audio stream via zeroconf (so other pulseaudio instances can see it)
load-module module-zeroconf-publish

# Publish the first alsa card as "Stereoanlage"
load-module module-alsa-card device_id=0 sink_name="Stereoanlage"

/etc/systemd/system/pulseaudio.service

Create the file:

[Unit]
Description=pulseaudio System Service

[Service]
type=simple
ExecStart=/usr/bin/pulseaudio --system --disallow-exit --disallow-module-loading
Restart=always
RestartSec=5

[Install]
WantedBy=multi-user.target

This defines a new systemd service called pulseaudio which will run pulseaudio

/boot/config.txt

Append to the file:

dtparam=audio=on
audio_pwm_mode=2

This change enables the audio DAC and provides an alsa soundcard.

Enable the services:

systemctl --global disable pulseaudio.service pulseaudio.socket # disable all user pulse audio
systemctl enable pulseaudio                                     # enable our systemwide pulse audio service
systemctl enable avahi-daemon                                   # enable zeroconf discovery

Reboot the Pi to enable the sound card:

reboot

After this, the pulseaudio sink is readily configured to be used with other pulseaudio installations

Auxiliary commands

Adjust volume

Use alsamixer to adjust the volume for PCM audio

dry run

This runs the pulseaudio like in the service

/usr/bin/pulseaudio --system --disallow-exit --disallow-module-loading

test alsa

This downloads a small example file (sounds like a coin in super mario world) and plays it via aplay to test if the soundcard works:

curl -O https://mq32.de/public/mariocoin.wav
aplay mariocoin.wav