Create multiple ShairportSync-Instances on the same Host with Airplay 2

[DerPicknicker]

Hey,

in this small writeup, I want to show you how to get multiple ShairportSync Instances running on the same Host including Airplay 2 support. Which is great because you can use an iOS-Device for syncing audio or MusicAssistant. This Writeup was inspired by this two Posts: Reference 1 and Reference 2

Requirements

• Basic Linux Knowledge
• Freshly installed Raspberry Pi with Raspbian OS Lite 64bit (or any other Linux distribution)
• SSH enabled and successfully connected

Used Hardware

In this Guide I used for a simple test this cool Audio-Hat which is compatible with an Pi Zero but with an Pi 5 you get 4 Mono Channels or 2 Stereo Outputs. For testing the Sync I connected an USB-Soundcard.

Recommendation

I tested this on a Pi Zero 2W which was working fine with 2 instances. The only problem I had was some Audio Dropouts. This is caused by the bad Wifi on the Pi Zero 2W. I highly recommend to use an Ethernet Connection if you're planning to use more than 2 instances on a Pi!

Updating and Upgrading your Pi

Before you start make sure your Pi is up2date.
Check for updates:
sudo apt-get update
Install the available updates:
sudo apt-get upgrade

Install required Software dependencies

We will build the Software from the Sources. For the build Process we need some Software and Libraries.

sudo apt install --no-install-recommends build-essential git autoconf automake libtool \
    libpopt-dev libconfig-dev libasound2-dev avahi-daemon libavahi-client-dev libssl-dev libsoxr-dev \
    libplist-dev libsodium-dev libavutil-dev libavcodec-dev libavformat-dev uuid-dev libgcrypt-dev xxd

Build NQPTP & Install

This Software is needed to run ShairportSync. We will also build that from the Sources. This process is quite straightforward:

git clone https://github.com/mikebrady/nqptp.git
cd nqptp
autoreconf -fi
./configure --with-systemd-startup
make
sudo make install
sudo systemctl enable nqptp
sudo systemctl start nqptp

Build ShairportSync

Finally we're able to build ShairportSync. It's as easy as with NQPTP:

git clone https://github.com/mikebrady/shairport-sync.git
cd shairport-sync
autoreconf -fi
./configure --sysconfdir=/etc --with-alsa \
    --with-soxr --with-avahi --with-ssl=openssl --with-systemd --with-airplay-2
make
sudo make install

Important Configuration Details of ShairPortSync

After the Installation we need to understand which Parts of the ShairPortSync Configuration are important for us. This Guide will only briefly cover the Configuration to keep this Guide as simple as possible.

• This is the Name shown on iOS Devices in the Airplay Menu: name = "Dining Room";
• This Port uses Shairport to receive Data one Port cannot been used twice: port = 5001;
• This is used to create multiple AirplayIDs the iOS Device needs different IDs per Instance: airplay_device_id_offset = 2;
• This is the Audio Device for the Shairport Instance, one Device cannot been used twice: output_device = "hw:Headphones";

Create a new Configuration

In this Section we will create a new Configuration. To check available Audio Outputs use the following command:
shairport-sync -h
At the end of that output you should see a list of the available Audio-Outputs. Note that down.

Create a copy of an existing ShairportSync Configuration

sudo cp /etc/shairport-sync.conf /etc/shairport-sync2.conf

Edit the Configuration of initial Shairport Instance

sudo nano /etc/shairport-sync.conf

1. Uncomment the name and set it to your needs e.g.:name = "Dining Room";
2. Uncomment output_device and set it according to the information of that command: shairport-sync -h
3. Save and Exit via CTRL+X

Edit the Configuration of 2nd Shairport Instance (repeat that for the number of Instances)

sudo nano /etc/shairport-sync2.conf

1. Uncomment the name and set it to your needs e.g.:name = "Dining Room";
2. Uncomment output_device and set it according to the information of that command: shairport-sync -h
3. Uncomment port = 5001; and increment it by one for each instance (EACH PORT CANNOT BEEN USED TWICE)
4. Paste this airplay_device_id_offset = 2 under Port and increment it by one for each instance
5. Save and Exit with CTLR + X

Create new Services

Assuming that you're happy with your previously created configurations of ShairPortSync we're now able to create the Services that ensures that ShairPortSync will start automatically.

1. Create a Copy of initial Service File: sudo cp /usr/lib/systemd/system/shairport-sync.service /usr/lib/systemd/system/shairport-sync2.service(repeat that based on the number of ShairPortSync Configurations)
2. Edit newly created Service File: sudo nano /usr/lib/systemd/system/shairport-sync2.service and update the ExecStart Argument: ExecStart=/usr/bin/shairport-sync -c /etc/shairport-sync2.conf (point to the Config file we created before).
3. Save and Exit with CTLR + X

Enable Services

sudo systemctl enable shairport-sync --now
sudo systemctl enable shairport-sync2 --now
sudo systemctl enable shairport-sync3 --now
(repeat that for each newly created Service file) 
...

Final Words

After this Guide you should be able to see multiple Airplay2 compatible Instances of ShairPortSync which are shown in the Airplay Menu of your iDevice. I tested this myself and tried to do it as detailed as possible. If something is unclear please comment here. For ShairPort related Issues this is not the place to discuss please create Issues / Discussions here.

[Se7enair]

Hey, great work!
I have a question for my understanding. You are sending audio via Airplay from a iOS device to a music assistant player? Which type of player are you using? Snapcast?
For me the biggest downside in using snapcast is thst I am loosing the grouping functionality in iOS. If I run multiple instances of shairport on my snapcast server I can link every shairport instance to one snapcast player?
That means on the "frontend" I use airplay, but on the backbone snapcast is used?

[DerPicknicker]

Hi @Se7enair

I just use MA to create Multiroom groups (they're playing in sync). On the iPhone I just play to a single player only. At some point MA will be capable of exposing players as AirPlay devices. Then my AirPlay Groups will be available also from an iPhone.
Because for me a Group is more intuitive than selecting each individual player.

I faced some issues do you have experience with PulseAudio? Because Shairport Sync is also available via Docker and for that I need a PulseAudio device.

Hope that helps - if you have any questions let me know.

[osresearch]

I'm doing a similar multi-zone setup with eight USB audio cards on a Pi5 (six on a USB3 hub and two plugged into the USB ports on the Pi itself). The biggest problem is assigning consistent names since USB doesn't always enumerate the same and the cheap cards don't have any serial numbers exposed. Instead I've hacked up a modified S99shairport-sync that uses the USB device path to extract the port that it is plugged into and look in /boot for a file with that name to name the airport device.

https://github.com/osresearch/shairport-pi/blob/main/rootfs/etc/init.d/S99shairport-sync

[DerPicknicker]

This is a Cool solution!