Core Machine (Operating system/System info/Roon build number)
Mac Mini MacOS version server OSX 10.10.5 / 2.5Gh Intel i5 4GB 1600GHz DDR3
Roon Core 1.7 build 710 stable
Network Details (Including networking gear model/manufacturer and if on WiFi/Ethernet)
Gigabit Ethernet Cat 5e all going through high grade gigabit switches
RAAT 100% reliable up to DSD256 no drop outs.
Audio Devices (Specify what device you’re using and its connection type - USB/HDMI/etc.)
Pioneer N-30 Network Audio Player used as bridge with coaxial digital out to Sennheiser HDVD800
When selecting Pioneer N-30 as an AirPlay device to act as an destination for streamed TIDAL, QOBUZ or local server based music. On occasion the resultant stream on Pioneer N-30 can suffer digital artifact distortion but only when tracks being played originate at 44.1 / 24 if higher resolution such as 88.2, 96 or 192 / 24 then non such distortions exists.
If however same affected tracks are played from iPad on iOS over AirPlay to N-30 from either QOBUZ OR TIDAL then distortion on affected track is NOT present.
Therefore, this particular issue is only Roon Core specific.
For reference Roon Core is well specified Mac mini dedicated to task built as a server connected only via gigabit Ethernet and cpu is only around 20% when Roon is playing requested track.
My belief is that since Roon does not use official Apple Mfi AirPlay stack but rather a third party emulation that there is slight compatibility issue with AirPlay version 1 which is used by Pioneer N-30 NAP and similar older gen AirPlay devices.
The problem is in part due to Airplay 1 only supporting 44.1 / 16 and the required 44.1 / 24 to 44.1 /16 dither algorithm used by the AirPlay sender on core is creating the distortion that effects certain frequencies creating a slight distortion effect much like slight over tracking errors that can affect bad recordings.
On AirPlay products such as Apple HomePod which uses AirPlay version 2 the problem does not occur at all when streaming from Roon to HomePod or at least can not be heard.
Hopefully, a Roon engineer will see this posting and make some determinations on a possible resolution.