Option for optimized performance for a single core and single zone playback [Not on Roadmap]

it’s not… You aren’t claiming that the networked stuff sounds different. If you were claiming that, then it would be.

Cool, cheers.

Having played around for several years with each of Roon, A+, JRiver and HQ Player, I have too have a slight preference for A+ in the direct connection to DAc via USB scenario. But, as Danny suggests, I found using a very lightweight endpoint and NAA solution to sound even better (allowing me to use a very powerful computer to do my processing, but separating it both through the NAA and through use of a fiber conversion to limit the ability of any noise to travel to and through the NAA to the DAC).

That still leaves me using A+ on my Macbook when I’m listening to headphones through my iFi DAC, but it is the only place I use that combination. Everywhere else the power of Roon (or the improvement brougt about by use of the NAA) wins.


You’re using USB connection right? Do you use any sort of ISO Regen + LPS with the USB? RFI / EMI / ground plane noise traverses from your electrically noisy computer via the USB cable to affect your USB DAC. this is why there are all sorts of products that try to clean that up.

Yep, already using an Uptone ISO REGEN + LPS-1 right before the Hugo2 (which itself heavily filters RFI and is really well shielded, per Rob Watts). The USB DAC input is well isolated.

Airborne RFI is something to consider, but the Mac housing is all metal and the DAC housing is all metal, which helps shield from RFI.

Devices with metal enclosure do not approximate faraday cages–remember, bluetooth, wifi, and air are passing in and out–at least. Computers are designed to be permeable.

In my experience, RFI produces the largest effect size of all of the “beyond bit perfect” interference mechanisms. It’s the first place I try to debug when things don’t sound right. And nearly 100% of my bad experiences with RFI have occurred in the presence of plenty of metal enclosures.

When I want to do critical listening for the purpose of evaluating gear, I take the absolute minimum amount of stuff into the middle of a room with no other equipment, and do the testing there with a pair of headphones. Ideally, just a power cable and ethernet cable connect that stuff to a Roon system in a closet far away. I don’t trust what I hear in my office–because there is so much equipment in here and I can’t hope to meaningfully control for who is radiating what.

I’ve reviewed dozens of devices since we launched Roon in 2015. I’ve seen some that like to amplify WiFi signals, some that like to amplify GPU activity, some that like to amplify RFI from the driver circuitry in my Thunderbolt monitor, and some that pick up cell phone signals. Usually when I notice this stuff, the effect size is huge–it’s not something where any would doubt the audibility. Remember back in the 90s when every amplifier would pick up and amplify GSM signals? I’ve run into some products that still do.

Of course, if a device is able to amplify interference to the point where it is unmistakably audible, it’s also amplifying lower-amplitude interference and causing more subtle problems at other times.

I want to stress-this is not just irresponsible manufacturers, and it is not just inexpensive products. Some devices that I like quite a lot, and would recommend to my friends have exhibited this kind of behavior.

There is just no substitute for physical space between the sound critical stuff and the stuff that isn’t engineered that way. The game of “making things radiate less” is moot by comparison. Yeah, you can do it to a point, and see some results, but it’s a much less interesting game.

Anyways–my one recommendation is to look into the system-level optimizations that Audirvana performs. Turning off Spotlight indexing, stuff like that–Roon doesn’t do that stuff, but you can definitely do it by hand if you want and see some of the same benefits.

I don’t think you’ll find that their communication with CoreAudio or their file handling is the source of the differences. If I had to bet–it’s the GPU/CPU load associated with Roon’s rich UI that makes the biggest difference. Not a whole lot we can do there within one machine.


Cheers Brian. As per my OP I am very much experienced with having networked endpoints with a powerful i7 Roon Core far away from all the endpoints. Actually I commented last year that moving the i7 out of the listening room provided one of the best improvements in the sound quality.

Having moved from a large double storey space to a small apartment I’m now down to a single Roon/Core combination in the office.

I’m very much aware there may be compromises with this setup and this may simply be one of these compromises.

A+ has to deal with the exact same setup so it may (must?) be airborne RFI due to CPU/GPU as you and Danny say. I’ll try Danny’s experiment tomorrow.

Yah, I know you’ve been around the block. I’m not sure I’ve shared my thoughts about RFI in as much detail before so I wanted to get them in writing. I think now that device manufacturers have gotten pretty good at managing USB and very good with Ethernet, this is one of the next frontiers for improvement. Can always hope…

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By the way, I know of another manufacturer who has the opinion that WiFi RFI is bad for sound quality, and says therefore Ethernet is superior. As with many audio debates, there is an opposite camp (from certain users of particular devices that have both WiFi and Ethernet input).

I’m certain most of the worlds best DAC designers will agree that RFI can be an issue and design to shield against it.

Having owned DACs designed by 2 of the best designers (Ted Smith and Rob Watts) I know from discussions with them that they design extensively to protect against the effects of EM/RFI.

At the same time, as Brian says, he has seen and heard the best come through Roon Labs for testing and still seen and heard that even the best gear out there is not fully immune.

I think it’s possible that people here are only thinking of RFI as interferring with the signal traveling down a USB cable to the DAC. We are bathed in RFI, and perhaps the sonic differences have more to do with how the RFI is interfering with the whole listening system, not just the DAC itself. I am only presenting this as a possibility worth exploring. I have neither the academic background, nor the equipment or experience to test thismyself.

Hi Mark, my DAC’s USB input is isolated (power, ground and data lines). On top of that Rob Watts will tell you he filters RF heavily.

So yes I agree, as I mentioned above, airborne RF is possibly one of the major culprits.

While I’ve known this already (I already heard the sonic improvement that comes with moving an i7 Core out of the listening space) I guess I didn’t expect to hear a difference between RFI (due to CPU/GPU loads as Danny and Brian hinted) between 2 apps… if that is the culprit here.

Danny, what kind evidence are you looking for when it comes to sound quality of Roon/RAAT?

The users gave the input can be experienced on. Have you compared A+/UPnP vs. Roon/RAAT? Do you claim that they have equivalent sound quality in your experience?

If the UPnP implementation is not terrible and the device is Roon Ready, it should be identical. If you hear otherwise, I’d be interested in a statistically relevant blind test that removes the chances of bias.


If you did, did they sound identical?

I’ve not done this test for all the RAAT devices we have that we have certified. We normally leave the audio parts of the certifications to the hardware manufacturer. They have all done the tests to verify the SQ is there.

However, we’ve actually gone one step further, and tapped the actual bits coming out of the other side… and they are identical (obviously). Both are pull protocols, so timing is driven by the clock in the device, and not the sender.

Danny, thank you again promptly getting back to me.

Your answer - diverting to third-party SQ tests - implies that you do not have internal experience comparing Roon/RAAT with other software, such as A+/UPnP. (Correct me if this is not the case).

Your response “However, we’ve actually gone one step further, and tapped the actual bits coming out of the other side… and they are identical (obviously)” also implies that you and/or Roon think that the “identical bits” would exclude the possibility of Roon having inferior sound quality in “networked stuff” compared to other products.

This thread is about sound quality which naturally involves listening to the sound. With all due respect, what is the basis of your statements referring to identical SQ in “networked stuff” in view that you have shared no information with us on your recent listening experience on the subject?

Let me share the relevant part of mines: I am user of Roon for about 9 months, I like numerous features and the convenience of your product. Have tested A+, JRiver, mConnect, they all sound noticeable different on my setup - Mac Mini (I7, SSD); PS Audio DirectSream (connected with Purist Audio ethernet cable through Apple router, WiFi off), VTL MB750, JM Lab Utopia speakers, Purist Audio Neptune Cables, PS Audio P3 regenerator, dedicated circuits for each amps and for the front end. I find JRiver and mConnect the most similar sounding and Roon is on the other end. Without attempting to rank the SQ I find that Roon has the widest and deepest soundstage, however it sounds “thinner” has “emphasized highs”, more overhangs and how another user (woodford) described: “brasher, splashy, hashy, spitty” see Sound Quality change with build 259.

Ironically, what drove me to these tests was Roon 259 build which sounded different compared to the previous release and was not able to revert back to verify what I was hearing Sound quality change and re-installing older builds . After these tests, I can now spot the differences between Roon, A+, JRiver in less than 30s on tracks I am familiar with.

I extend my invitation to you and two colleges of your choice to listen and decide on your own. I live in Austin Texas.

Please allow me to point it out that I find it disrespectful to tell users/clients in this thread: “you can keep your antecedal evidence to yourself until you have an explanation that can be reproduced and experimented on”. (i) first as mentioned above you have not shared with us “a statistically relevant blind test that removes the chances of bias” to prove that Roon has identical SQ in “networked stuff” compared to other products. So, on what ground would you ask a rebuttal evidence?; (ii) the users in this thread did point to A+/UPnP vs. Roon/RAAT which can be experimented on; (iii) asking us to have an explanation does not fit to the posture of us being the user of the product and clients of Roon; lastly you do not need to know why a rotten egg stinks to be able to determine that is rotten.

My reply could sound blunt may be edgy, but I want to get my point through clear: I do not think that Roon has the appropriate focus on sound quality

To be fair, it’s worth referencing these two quotes from the Roon team:


I think I would sum up Roon’s position as this: the data coming out of our system is bit-identical to the data coming out of other product XYZ, but it’s possible that the cpu intensive Roon UI is generating higher cpu/gpu load and causing downstream RFI/electrical USB interference at the D/A process in a DAC. Moving the Roon core/UI away from the USB connection will mitigate this.

it would be interesting to see if anyone can validate/nullify @danny’s hypothesis - does loading up the cpu while using A+, via Roon UI or otherwise, cause the SQ to level out??

I haven’t done that specific test (yet) but I have monitored cpu activity on my mac mini and while the Roon UI does use additional cpu cycles, I find it a stretch to believe that this would cause sufficient RFI/electrical USB noise to the extent that it’s so obviously audible. That said, I would be very happy to have my doubt removed with good evidence.

FYI only (related to the subject being discussed, but not directly related to Roon) :

For something more related to Roon: If we look at Sound Galleries (a Roon partner) music server, it also states “Fully optimising the operating system to only run the processes necessary for HQPlayer and roon to work.”

If you are talking about single computer then Roon has clearly stated that it has made a decision to offer a graphics rich heavy UI that is not as light or optimised for audio as other products. That isn’t going to change. Roon’s UI is at the heart of the product.

Roon reccomends separating the Core, Control and Output functions into different devices. When people compare that architecture to other products, they don’t hear a difference.

Single computer SQ is important to the Roon devs, but it is not the reccomended architecture for maximising SQ.