Signal Path when Roon is polling files from remote NAS


I have Roon Core installed in Mac Mini. My songs/files are in a separate NAS/Shared Folder which is remote to Roon (connected over ethernet). My Roon player is a RAAT based Streamer (PS Audio Bridge 2) connected over ethernet.

The signal path showed by Roon is : Source -> PS Audio (RAAT) -> Output (Analog Output)

The Qs is - Does this mean that the File Stream flows directly from my NAS to P S Audio Bridge (without going through Mac Mini) ?

Now if I change my output from P S Audio Bridge 2 to P S Audio USB input, the signal path shows - Source -> Mac Mini (RAAT) -> Output (Core Audio in Exclusive Mode) . So does that mean in this case the File Stream flows from my NAS to Mac Mini to P S Audio ?


The data flow is always via the core regardless of the physical location of the files themselves. in your case the core is always fetching file data from your NAS, but this step isn’t shown in signal path (it’s just called “source”).

Thanks Andrew for your input.

In that case is there a way to improve the sound quality (apart from running Roon Core on my NAS or loading files in my Mac Mini) ?


The location of the files in relation to the core has no impact on sound quality. The hardware running the core has no impact on sound quality. The OS on the core has no impact on sound quality. The only time that the core has any impact on sound quality is if it is directly connected to the DAC (USB, HDMI, S/PDIF) and in that case it’s an issue of noise bleeding into the system via the physical connection.

The two primary factors determining sound quality are going to be the hardware and implementation of the Roon output device connected to the DAC (the PS Audio bridge in your case) and the quality of the DAC and its interface to the bridge.

The internet fora are rife with discussion of “this core / network configuration sounds better than that one”, but in reality “playback” doesn’t start until bits are moving out of the memory buffer on the bridge device. Everything else is just data transfer and that in itself has nothing to do with digital to analog conversion.

Now, keep in mind that there are things that you can do with your core/network which can have an impact (such as physical location of the core in relation to the audio gear and ground isolation between the network and the stereo), but these are more of a universal “best practices” type of thing than anything specific to Roon.

Hi Andrew,

My concern was more around the fact that in case Core is running remote to the NAS (where file is stored), the actual data needs to move over the network twice - first from NAS to the machine where the Core is running (in my case the Mac Mini) and then from Mac Mini to P S Audio Bridge.

Though I know reliability wise there should not be any data loss, but wondering whether this extra hop causes any SQ degradation or not.


No, it doesn’t and, in fact, the amount of data being transferred twice isn’t remotely straining on the network controller.

16/44.1 (CD) data has a data rate of 1411 kilobits/sec.
24/384 (DXD) data has a data rate of 18,432 kilobits /sec.

The gigabit network interface on your core / NAS has a data rate of…

1,000,000 kilobits / sec.

So reading a DXD file from your NAS and streaming it to your bridge uses less than 4% of the total available bandwidth, but since Ethernet is full-duplex that’s really closer to 2%. You could conceivably stream a DXD file to 20 separate bridges simultaneously and still not top-out the network interface.

That’s great explanation Andrew. Thanks a lot.

Now I’m wondering why (in various forums I found posts) people are so particular about keeping the data files local to the Music Server processors (Roon or other servers like jRiver, Minim, etc.). I personally like this architecture of keeping data file and music server processor separate so that I can manage and scale them separately.


I can’t comment on why as there’s no technical reason for a benefit one way or another, but some are absolutely convinced that this makes a difference. Sadly this hobby tends to breed dogma and the internet has a nasty habit of spreading that as if it’s truth.

Try it both ways for yourself and see if it makes a difference for you then go from there.

I’ve done that and there was no benefit to local storage. I end up using both methods, but then I’m running a more complex setup than most (multiple Roon cores, JRiver, and multiple minimserver instances).