I started my DietPi on Raspberry Pi 3 optimisation. This device is used as a Roon Bridge and Apple Airplay end point. Apple Airplay is being used to stream Qobuz from my iPad until Roon includes this service + various other services occasionally. I use the Allo Digione Signature hat cause the USB output SQ of the Raspberry Pi is low.
This topic is to share optimizations that may improve the overall SQ of this cheap but quite good device. So feel free to share your learnings.
My setup is as following:
- HDMI is off
- Ethernet is off, only WiFi
- Bluetooth is off
- CPU is in powersave mode
- CPU is in fixed frequency (600 MHz)
- All Linux processes are running on core 0
- All Roon Bridge processes are running on cores 1 & 2 in SCHED_RR schedule policy (real time) and priority 99 (maximum). Nice is also set to -20, may be redundant or of no use.
- All Shairport processes are running on core 3 with similar options than Roon.
Overall SQ has been improved, especially dynamics and bass.
I used to use additional ALSA settings with Daphile (buffer time and period count). Those settings were having huge impact on SQ. But my knowledge in ALSA is not good enough to find where those settings were located. If one can help.
----- Edit 16th of december 2018 : CPU fixed frequency added