Maximizing sound quality with Roon?

Streaming Audio
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Hi Micheal,

Is it really necessary to transcode from FLAC to WAV considering you’re using a Roon Server?

When using an UPnP server, the point of transcoding from FLAC to WAV was to avoid the streamer to decompress the FLAC files, and therefore minimize the processing power.

This is unnecessary in the context of a Roon Server.

Whatever file format your PCM files are (AIFF, ALAC, FLAC or WAV) the Roon server will send pure LPCM.

All the decompression job is done on the server side. The ND555 only receives a LPCM stream.

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The way I read it, perhaps Michael means that Roon always sends PCM to the streamer/endpoint. As far as I’m aware, the Roon Core cannot transcode FLAC to WAV on the fly in the way that some UPnP servers can.

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That’s what I read too.

Roon sends only pure LPCM, DSD or MQA streams to the Roon Endpoints.
It doesn’t send container files like WAV, FLAC, ALAC, DSF, DFF, etc.

I didn’t quite understand the FLAC to WAV transcoding Micheal was referring too.

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NUC10i5 with 16GB RAM, 256gGB m.2 SSD running ROCK is currently my take on the sweet spot for Roon devices.

Currently run it in an iMac and whilst it’s fine I want an appliance (turn on, off) not a computer (boot, shutdown, fiddle).

At or above 8th gen allow you to turn fan either off (dodgy) or down a lot (so it hardly runs); later gens are not much more than earlier ones; i5 good balance between processing power and unnecessary heat; 16GB more than enough but only a few ££ more than 8GB; 256 GB SD HDD is fastest for run-in the Roon database on, with music files elsewhere on a NAS, or you can put them on an internal drive in the NUC if you get the right one.

Futureproof, cost effective, reliable.

But cheapest is an early NUC with i3 and 8GB RAM, which will be perfectly adequate for now.

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Correct, Roon sends either PCM or DSD … file types are irrelevant, as they are read and decoded on the fly by the core, well away from the streamer end point … and RAAT simply sends the PCM or DSD media.
There is no benefit in transcoding at all as Roon forcefully transcodes and sends the digital audio to the end points anyway.

This is rather different to UPnP which sends different MIME media types to the endpoint that may have to be transcoded. This is a key benefit of the Roon RAAT system.

I can confirm the sound playback of various files read and decoded by the Core (FLAC, AIFF, ALAC, WAV) and sent via RAAT over Ethernet sound completely identical. Not even the subtlest of shifts or changes in colour. Roon Core is effectively a media aggregator… it really is a major liberation over some other techniques.

I use an OSX iMac Core.

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You, @Thomas and @Simon-in-Suffolk are entirely correct. I had a brain malfunction: the transcoding reference was a hark back to the NAS I had before the Roon Nucleus, whereas now the FLAC files are of course transcoded to PCM and sent to the ND555 as such.

Like Simon I have compared very hi-res WAV and FLAC files of the same recording using Roon and could tell no difference.

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I’d like to offer my take as well, so those reading this thread later can have an alternate view. This relates specifically to running Rock on an Intel NUC.

(Sorry, Joppe - this is not related to maximizing sound quality of Roon.)

RAM usage for Roon is primarily driven by number of tracks. 8GB will support around 300-500,000 tracks, depending on metadata usage. Over that and you’re in rarified territory; 16GB will get you closer to 1 million tracks.

Roon is an extremely light application and is purposefully designed to be so. It is not designed to use RAM just because it’s there and it simply crashes if memory is not sufficient for the tracks it is attempting to work with.

So, 8GB RAM is more than sufficient for the significant majority of cases. (Roon themselves suggest 4-8GB.)

Single-core CPU performance is frequently cited as a key metric for Roon. CPU core requirements go up as you increase the number of concurrent playback zones and add filters/DSP. (I believe one core is spun up initially per zone and processing stress increases with application of filters/DSP.)

The current crop of 10th gen CPUs in Intel NUCs appear to be focused on increased compute per watt relative to prior generations (15W TDP across the board) and the number of cores increase (2, 4, 6) as you go up the range. Single-core performance does not seem to be that, if any, different between a current i3, i5 or i7.

So, unless you have significant multiple, concurrent zone needs (over four?)*, the current i3 is more than capable for most needs.

Don’t take my word for it, though. @simon.pepper (plus others) benchmarked his 5th gen i3 over on the Roon forums (look for “List Your NUC Capabilities”, for those interested). Key takeaway? It more than held its own against later gen i3, i5 and i7 systems.

I don’t personally subscribe to the idea of buying headroom for “possible future needs” when it comes to Rock on a NUC, given the current design strategy.

My personal choice is an i3 with 8GB RAM - I run two zones at most and do not have 300k tracks. The savings against an i5 with 16GB paid for a year of Roon.

*Roon’s own Nucleus specs, based on an i3, suggest support for up to 6 zones.

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Interesting views, thanks

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I have a 2012 MM with 16 GB RAM, I have found it is more than enough for the Roon Sever with some simple DSP. However, I find it really is struggling if I do DSP up sampling to DSD128.

Btw, I find something odd with Roon search - basically if I search for something simple like “années 80”, the results always come back with tracks, albums, artists, but never a playlist. What I am actually looking for, in this case, any playlist that has the pattern “années 80” like Rock années 80, etc.

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Roon search doesnt look for playlists in the streaming services unless they are added to your local library already as a playlist. You have to manually look in the Tidal or Qobuz sections for that.

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Yes, upsampling/converting to DSD can be very CPU intensive.

I also have a Mac mini from 2012. I found Roon “processing speed” practically identical to a current i3 10th gen NUC (this was for down-sampling e.g. from 96/24).

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Thanks for the cirrus7 pointer, found some positive posts, ordered the nimbini Media edition, I’ll let you know :slight_smile:

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Do you happen to know a link to the license? I googled and searched the Roonlabs website but found nothing. Thanks!

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Please let us know how you find it. As you probably seen I decided on a 10th generation nuc in the end but nonetheless interested in your feedback on the Cirrus7.
You find a hyperlink to download Rock in the installation guide on Roonlabs homepage.

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Sorry I dont . I just know this as its been said by the CTO and CEO many time. 3rd parties are not allowed to distribute Roon code with products unless they have an agreement with Roon to do this and then this is rare. But Rock is download and install only. They are free mind to everyone to use them they just have to download them from Roons servers then install them themselves.

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Yes, seen later. Me too, I got the 10th Gen i5, seems to be the sweet spot. It was difficult to resist overspending as it was just 50 Euros here and 100 there :slight_smile:
So I ended up with 16 GB RAM, the 970 EVO Plus 250GB for the database, and the 860 EVO 4TB for music. All of which is way more than I will ever need, but this was kind of the point as it is the final piece in my new system (no, really this time!) and I intended to do this once now and be set forever (or something).

I ordered it with Rock preinstalled too, you didn’t? I didn’t want the faff, it’s time to listen to music, finally. How do you like it now?

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Thanks, obviously the terms are entirely Roon’s decision. It’s just that if they want the license to be heeded it would be a good idea to put it online on the Rock page, as is customary for downloadable software releases. And I’d be really interested in reading it.

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