Raspberry release notes

LXQt Desktop, roonbridge, lms, squeezelite, mpd with UPnP, airplay, NoMachine, kernel low latency archlinuxarm with threadirqs enabled
HQPlayer Network Audio Daemon on 32 bit version with raspberry kernel

The 64 bit version is using the very last kernel 4.19, but if you want the usual raspberry drivers (for example if you use Allo DigiOne) you must use the other version.

MPD configuration file: /home/audiolinux/.mpdconf
SQUEEZELITE configuration file: /etc/conf.d/squeezelite

For Allo DigiOne, you should add the line
to /boot/config.txt

For Metrum Ambre, you should add the line
to /boot/config.txt

For a better performance, you can (as root):

1) Disable LXQt Desktop with
systemctl disable sddm

2) Disable Nomachine remote Desktop with
systemctl disable nxserver

3) Add the following configuration in /boot/config.txt taking out # in front of the lines*:
arm_freq=1200 # default 600. max 1400 on rpi3 B+
core_freq=500 # default 250
force_turbo=1# Prevent regulation of speed down to 600Mhz when idling
boot_delay=1 # Avoid sdcard corruption when force_turbo is enabled

* enabling turbo mode could invalidate warranty, overclocking Raspberry is at your risk

4) Blacklist Bluetooth, WiFi or internal audio card taking out # in front of the lines in /etc/modprobe.d/blacklist.conf
# Backlist bluetooth
blacklist bluetooth
blacklist btqca
blacklist btsdio
blacklist btintel
blacklist hci_uart
blacklist btbcm

# Blacklist WiFi
blacklist brcmfmac
blacklist brcmutil
blacklist cfg80211
blacklist rfkill

# Blacklist internal audio card
blacklist snd_rawmidi
blacklist snd_usbmidi_lib
blacklist snd_seq_device
blacklist snd_bcm2835

With these optimization you can have a nice CPU latency:

[audiolinux@raspberry rt-tests]$ ./cyclictest  -l 10000 -m -Sp98 -i100 -d0
# /dev/cpu_dma_latency set to 0us
policy: fifo: loadavg: 1.24 0.34 0.12 1/187 548         

T: 0 (  545) P:98 I:100 C:  10000 Min:      5 Act:    5 Avg:    6 Max:      62
T: 1 (  546) P:98 I:100 C:   9879 Min:      5 Act:    7 Avg:    5 Max:      32
T: 2 (  547) P:98 I:100 C:   9802 Min:      5 Act:    9 Avg:    6 Max:      41
T: 3 (  548) P:98 I:100 C:   9686 Min:      5 Act:    7 Avg:    5 Max:      38