Roon and the Roon Nucleus+

tmallin

WBF Technical Expert
May 19, 2010
549
124
455
68
Chicagoland
I am cross-posting below a few posts dealing with this new topic which as first wrote as part of my thread dealing with the Lumin X1. I fear that they otherwise might get "lost" since nothing in the title of that thread indicates that it deals with Roon. Anything further I have to say about Roon or the Nucleus+ will be in this thread.
 

tmallin

WBF Technical Expert
May 19, 2010
549
124
455
68
Chicagoland
April 28, 2020

As I write this, my current system is Lumin X1 using its digital volume control > pair of bridged-to-mono Benchmark AHB2 amps > Gradient 1.4 speakers. I use an iPad Pro to control Roon and the Lumin app. The Roon core (which also hosts my music library and MinimServer) is a general purpose computer, albeit a powerful one: Dell XPS 7760 AIO Signature Edition with Intel Core i7-7700K CPU at 4.2 GHz with 64 GB RAM running Windows 10 64-bit.

As I've said before, computer audio is certainly fascinating. When I last wrote about Roon, it was back in August 2019 in my thread dealing with the Lumin U1 Mini + SBooster Power Supply, post #8. There I said, about Roon in comparison to the Lumin App:

Roon may offer a yet-slicker interface than the Lumin App if you need/want one. I've just downloaded the trial version and began to use that over the last weekend. Talk about being able to go down a musical rabbit hole! Roon opens possibilities for musical exploration I never dreamed about before, but I'm not really sure the audiophile in me needs this level of musical inter-relatedness.
Sonically (with the exception of the DSP equalization opportunity Roon affords!), the Lumin App is at least as good if not better in my setup, so the differences so far are purely how the music is organized and inter-related. I probably will comment further on Roon after I get more experience with it. Many music lovers swear by Roon, but already I can tell that it is not really classical music oriented in terms of the "deep knowledge" it offers.

Roon recently released a new version, Version1.7 build 537. I installed that update a few days ago. I agree with other WBF comments about this new version. This is a significant and very worthwhile sonic upgrade. While the Roon interface already was the best, previous to this update, I regarded the sonic quality of Roon in my system as at least a bit bright/edgy and less three-dimensional compared to that of the Lumin App fed via MinimServer. Now, after the update, while the Lumin app still sounds slightly better, the difference is much less, so much less that the superiority of the Roon interface would probably make it my "go-to" for all but the most serious of listening. I put my money where my mouth is and converted to the Roon lifetime plan from the annual plan, shelling out $700 to do this.

In addition, as one review of Roon's Nucleus+ has mentioned, Roon's upsampling/resampling function sounds exceptionally good. It does not add brightness or reduce bass. The general tonality remains very natural with the highs gaining added clarity, the background added blackness, the staging size in all dimensions, and the imaging added roundness with equal stability.

I have experimented with various levels of Roon's upsampling/oversampling. Since the Lumin X1 accepts PCM inputs of up to 768 kbps and 32 bits, I tried all the levels up to that maximum, which is Roon's maximum offering. Generally speaking, the more upsampling of 44.1k or 48k material, the better sounding the result with the new Roon build.

Even with this level of upsampling/resampling, Roon is telling me that the available processing is at a level of about 9. Apparently, as long as your available processing level is above 1, you have sufficient computing power to perform the requested processing. As expected, if I cut back the oversampling/resampling to 352.3 or 384, the processing available is at twice that level, 18. With 705.6 or 768 upsampling/resampling, I can still watch Netflix HD movies on the same computer with no problem. My computer's Task manager indicates that with Roon doing 705.6/32-bit upsampling/resampling, Roon is taking about 2% of my computer's CPU capacity.

At least for the time being, I am now using Roon as my go-to music streamer. It's definitely the slickest interface and now it also sounds at least as good as the Lumin App.

When using Roon, I have the Lumin App settings with the Lumin App's Roon Ready and Lumin Streaming (aka AirPlay) functions enabled. With those settings, the Lumin App can be turned off. My iPad controller can then use the Roon app to select music and control the volume. Any streams which Roon cannot natively handle (e.g., Sirius/XM or Jazz Radio) can be selected from an app on the iPad or from a Safari bookmark on the iPad. These sources then stream to the Lumin via AirPlay/Lumin Streaming from the iPad. With this configuration, the Roon volume control controls all streams, even the AirPlay/Lumin Streaming ones.

Interestingly, as long as the Roon Core is operating (as in the Roon program is open or minimized on my computer desktop), then neither the Lumin App nor the Roon App needs to be turned on on the iPad controller. The music continues to stream. The iPad can even be powered down--same result. The volume and program choices (except for AirPlay/Lumin Streaming) can be adjusted and controlled from my desktop computer. Thus, if I'm working at my computer desk (as I am now) and just want my primary audio system to play background music, I can control the volume and streaming program for the audio system in the other room from my Roon Core computer desktop.
 

tmallin

WBF Technical Expert
May 19, 2010
549
124
455
68
Chicagoland
May 7, 2020

I can now heartily recommend the Roon software and the Roon Nucleus+ (Plus) as a server. Yes, I took the full Roon plunge (or at least a much fuller plunge) and purchased the Nucleus+, moving my music files and serving off my general-purpose computer. I now have my music files on a 1TB Patriot Supersonic Rage Elite USB 3.1 stick inserted into one of the two USB ports on the back of the Nucleus+.

As I've noted, previous iterations of the Roon software sounded a bit bright and edgy to me in comparison with the same music files sources from my networked computer, Tidal, or Qobuz played via the Lumin App through my Lumin X1.

With the latest iteration of the software and firmware, however, those objections have disappeared. Now there is no sonic impediment to enjoying the superior Roon user interface and metadata. My move to the Nucleus+ as my music server has only served to reinforce my evaluation of Roon's current sonic presentation. Moving to the Nucleus+ resulted in more solid and defined bass, greater overall clarity and relaxed/analog-like quality of the entire presentation, as well as better imaging and staging. I don't hear any downsides.

Plus, moving the music serving off my general purpose computer frees up that computer's memory and CPU load Roon's serving and resampling was presenting. That computer now offers even faster performance and better HD movie streaming quality, both for video and audio.

With the Nucleus+ as server, I believe the maximum PCM resampling levels (705.6 or 768 kHz/32 bit) provide the best sonics feeding my Lumin X1. The Lumin X1 is one of the few DACs which accepts that bit rate and depth. I could also stream DSD up to 512 into the Lumin from the Roon's resampler, but, to my ears, high-bit-rate PCM resampling sounds better than resampling to DSD, either via the Roon's resampling or the Lumin's built-in resampling of PCM to DSD.

In addition, for a "throw in" with the purchase of the Roon software, you get a powerful suite of DSP. I have not explored the parametric EQ DSP yet, but the upsampling/resampling functions are the first such which I've found to be all to the good, especially for 44.1/16 or 44.1/24 material, from internet radio through CD quality material.

The cost of my Roon investment is not low, at $699 for a lifetime Roon subscription and $2,500 for the Nucleus+, but that total is less than some high-end one-meter cables, so you be the judge.
 

tmallin

WBF Technical Expert
May 19, 2010
549
124
455
68
Chicagoland
May 17, 2020

In the post above I said:

With the Nucleus+ as server, I believe the maximum PCM resampling levels (705.6 or 768 kHz/32 bit) provide the best sonics feeding my Lumin X1. The Lumin X1 is one of the few DACs which accepts that bit rate and depth. I could also stream DSD up to 512 into the Lumin from the Roon's resampler, but, to my ears, high-bit-rate PCM resampling sounds better than resampling to DSD, either via the Roon's resampling or the Lumin's built-in resampling of PCM to DSD.

Further listening via the Nucleus+ has caused me to change my mind about the DSD resampling. Resampling via the higher DSD rates (256 and 512) sound smoother in the mid and high frequencies, more analog like, yet equally detailed when compared with the highest PCM resampling levels. A/B comparisons of various resampling options have led me to use the DSD 512 sample rate conversion with 7th order CLANS DSD processing settings. I have enabled "Parallelize Sigma Delta Modulator" but I do not "Enable Native DSD Processing" both because I don't have any native DSD program material and because I think it sounds better not to enable this function.

But I have also noticed that with the Nucleus+ I now often find MQA recordings on Tidal to be at least as good sounding as the best high-res PCM version of that recording on Qobuz. Roon does not resample MQA recordings so with MQA recordings on Tidal none of Roon's resampling choices are available. The MQA version sonically differs from the PCM in somewhat the same way that DSD resampling differs from high-bit-rate PCM resampling. The MQA sounds warmer, more relaxed, more analog-like. High-Res PCM recordings on Qobuz still sound more detailed in the mid and high frequencies (whether or not DSD resampling is applied to them), but by comparison to the MQA version on Tidal, the high-res PCM versions on Qobuz (DSD resampled by Roon or not) sound just a tiny bit bright and edgy. Unlike DSD resampling, MQA seems to warm up the lower frequencies and mids a bit, adding yet more analog-like warmth to the sound. But I admit that these judgments might be different if my current Gradient 1.4 speakers were balanced more warmly--say like my prior Harbeth M40.2 speakers were.
 
Last edited:

tmallin

WBF Technical Expert
May 19, 2010
549
124
455
68
Chicagoland
May 27, 2020

In the Darko Audio review of the Roon Nucleus+, reviewer Steven Plaskin said:

While the Nucleus+ comes with its own SMPS (Switch Mode Power Supply) that is rated at 19v / 3.42 amps, substitution of the power supply with a quieter SMPS or linear power supply can enhance the overall performance of the server by adding less noise to the overall system. I tried a 200-watt HDPlex linear power supply and an SOtM sPS-500 (SMPS) to see if there were appreciable improvements observed in sound quality. I found the HDPlex to have the best sound in my system with a general reduction in overall ‘brightness’.

Other comments on the Nucleus and Nucleus+ sound quality have also mentioned improved sound quality when the stock SMPS is replaced with a suitable linear power supply. Roon itself does not deny this effect, but I don't believe recommends a specific linear power supply at this point. Favorable comments about the after-market power supplies from Keces in both the Roon and Lumin online communities led me to order the Keces P8 model which costs about $700, including express shipping from Taiwan.

The Keces P8 arrived only a few days later at my Chicago-area address even over the Memorial Day holiday--impressively fast order processing and shipping. The packaging was bulletproof and the unit itself appears handsome and extremely well built. It's 8-amp output is fully twice the rating of the stock power supply. I did need to use the included adaptor on the Nucleus+ end of the DC cable since the Roon device has a larger center pin on its DC power receptacle than does the Keces.

While the unit has only been in my system for less than 24 hours at this point and thus further break-in may well occur, I already feel confident in recommending such a linear power supply to users of the Nucleus+. From the first couple of seconds of play, with the Keces P8 stone cold, the background took on a greater "blackness," the bass was enhanced in punch and definition, the soundstage gained size in all dimensions, imaging was yet-more focused and three-dimensionally rounded, the mid-high frequencies were definitely less edgy-bright while the very top was airier. These sonic improvements were not of the extremely slight variety, but were quite apparent and significant.

Yes, the price may seem high. But the substitution of a good linear power supply for the stock SMPS makes a shocking improvement in the already excellent sound quality of streaming via the Roon Nucleus+ in my system. I'll add further comments below if further warm-up/break-in reveal additional sonic improvements.
 

gds7368

Well-Known Member
Jan 9, 2015
62
34
225
Very informative and helpful review! Thanks. I just added a Keces P8 LPS to my Roon Nucleus Plus and it’s not a subtle improvement (even brand new). Really immediately better. Stored music already sounded good (consistency beating streaming) but I was shocked how much improvement there was in streamed music. Night and day. That’s with a new P8 and the stock power cord, and I just added a Valhalla2 power cord to the Keces to see where that takes the sound.

However, last night I listened to my business partner’s all MSB system, including Select2 DAC, Select transport, and S500 stereo amplifier. No streaming. His transport based system was significantly more dynamic, smooth, and lifelike than my K8/Nucleus+ with a stock power cord.

Of course (1) he wasn’t using a stock power cord on his transport, and (2) he was limited to his stack of music, and I can play almost anything (11 TB of music on my NAS, plus Tidal, plus Qobuz) and (3) that is comparing a $2500 music server to a $24,500 transport.

I share your enthusiasm for Roon. What a great way to listen to music, and I couldn’t imagine going back to changing every disc. I burned all my music to my NAS and sold all my discs about 3 years ago. But there is still a delta in sound comparing a Nucleus+ to a quality transport, at least with a stock power cord. I’ll listen with the upgraded power cord and see how much - if any - the gap closes. I’m breaking in the Keces this week as well. And I bought an upgraded cable from Ghent Audio to go from the P8 to the Nucleus+ (cable just shipped).

https://www.ghentaudio.com/part/dc-4s6g.html

A work in progress.
 
Last edited:

tmallin

WBF Technical Expert
May 19, 2010
549
124
455
68
Chicagoland
The quality of sound available from Roon--and indeed straight from my Lumin X1 streaming DAC via the Lumin App (and all other Lumin streamers) just took a leap up. Lumin has just incorporated Leedh volume control processing in its new firmware which I just downloaded after its release today. It's version 13.0, dated June 3, 2020. It's a new day for digital volume controls!

This algorithm claims to be a lossless form of digital volume attenuation. This is just what a system like mine, which relies on the Lumin X1's digital volume control directly driving my Benchmark AHB2 amps--needs. For information about this development from a French company, see this Darko Audio write-up as well as Lumin's own statement here.

Roon verifies in its DSP signal path flow chart that the signal going to the Lumin via Roon is being processed by a DSP volume control in the Lumin. That indication was not there before.

What's the sonic difference? It's early yet, but so far I'd call it greater clarity and immediacy, lower-yet apparent distortion, together with larger-yet soundstaging in all dimensions and more solid imaging--the usual audiophile desiderata. This effect seems audible on all signals from low-quality internet radio streams up through high resolution programs.
 

LeBlanc

Member
Aug 14, 2019
54
21
15
The Netherlands
Very informative and helpful review! Thanks. I just added a Keces P8 LPS to my Roon Nucleus Plus and it’s not a subtle improvement (even brand new). Really immediately better. Stored music already sounded good (consistency beating streaming) but I was shocked how much improvement there was in streamed music. Night and day. That’s with a new P8 and the stock power cord, and I just added a Valhalla2 power cord to the Keces to see where that takes the sound.

However, last night I listened to my business partner’s all MSB system, including Select2 DAC, Select transport, and S500 stereo amplifier. No streaming. His transport based system was significantly more dynamic, smooth, and lifelike than my K8/Nucleus+ with a stock power cord.

Of course (1) he wasn’t using a stock power cord on his transport, and (2) he was limited to his stack of music, and I can play almost anything (11 TB of music on my NAS, plus Tidal, plus Qobuz) and (3) that is comparing a $2500 music server to a $24,500 transport.

I share your enthusiasm for Roon. What a great way to listen to music, and I couldn’t imagine going back to changing every disc. I burned all my music to my NAS and sold all my discs about 3 years ago. But there is still a delta in sound comparing a Nucleus+ to a quality transport, at least with a stock power cord. I’ll listen with the upgraded power cord and see how much - if any - the gap closes. I’m breaking in the Keces this week as well. And I bought an upgraded cable from Ghent Audio to go from the P8 to the Nucleus+ (cable just shipped).

https://www.ghentaudio.com/part/dc-4s6g.html

A work in progress.

If I understand your system topology correctly, your Nucleus is connected directly to your DAC with USB. Note this is not the intended use case for the Nucleus.
 

tmallin

WBF Technical Expert
May 19, 2010
549
124
455
68
Chicagoland
LeBlanc, I think your comment about system topology is aimed at gds7368, not me. But just in case you are asking about my system topology, I do not connect my Nucleus+ directly to my DAC with USB. I do not currently use any USB cables in my main audio system.

My Nucleus+ is connected via three feet of Blue Jeans Cable Cat 6A ethernet cable to my Comcast Advanced Gateway modem/router in the dining room of my home which is on the first floor of the house directly beneath my second floor audio room. I use the stock DC and power cords for the modem/router, Nucleus+, and Keces P8 power supply. Keeping these items out of my audio room guards against the sonic contamination of the fan in the Comcast Advanced Gateway and the possible EMI/RFI from the high-speed computer guts of the Nucleus+.

The Comcast Advanced Gateway sends Wi-Fi signals 10 feet or so straight up to my audio room through the ceiling and floor where it is picked up by a TP link wireless access point in my audio room. The rest of my set up is described pretty well in a prior post of mine. One change from that description is that I'm now using an iPad Pro as my Roon controller in my audio room.

Eventually I will probably add an ethernet connection between the Comcast Advanced Gateway in the room below to my audio room and connect that directly to my Lumin X1. But my home is over 100 years old and has plaster and lathe walls and ceilings, plus horizontal fire-stop wooden barriers built in between vertical studs. This makes running wires a nightmare as I know from prior experience hiring an electrician to add two dedicated power lines to the same wall in my audio room where I'd want the ethernet jack. What should have been a short run from the electrical panel to my audio room turned out to require a long feed through the furnace chimney stack, my audio room closet, up into the attic and then back down through my audio room wall, well over 100 feet, at a cost to me of over $2,000 for the investigation and labor involved in this job. I would not want to run the ethernet cable through the same conduit as the power cable, so another big job would be involved.
 

tmallin

WBF Technical Expert
May 19, 2010
549
124
455
68
Chicagoland
I listened more late last night, after I wrote post #7 above. Even at extremely low volume levels (didn't want to wake my sleeping spouse, of course!) of between 8 to 10 on the 100-point volume scale ("normal" high volume for me in this system is about 72 or so), the added clarity and transparency were amazing. It's like I suddenly had Quad 57s or some other speaker known for extreme transparency even at very low volume levels.

The Leedh volume processing can be toggled on and off at will within the Lumin App for comparison. The switchover takes less than five seconds. Thus, pretty good A/B testing of the Leedh processing is available. (This assumes, of course, that Lumin has not somehow "dumbed down" the volume control when Leedh is not engaged in the new firmware. There's no way to quickly A/B the new version of the firmware with the old version.) The difference is the proverbial "night and day." And this is even though the direct connection before seemed surprisingly sonically purer than using the special relay-controlled volume control of my Benchmark HPA4 "preamp" which I thought was pretty special indeed at the time.
 

tmallin

WBF Technical Expert
May 19, 2010
549
124
455
68
Chicagoland
Here's a description of a new way to add new music to your library once you have a Roon subscription as well as Tidal and/or Qubuz.

One of the features Roon has incorporated into its software is the ability to quickly and easily find a high quality version of a song you are playing via an internet radio station, play the high quality version, and add that song or its album to your library. The whole process takes just a few seconds and a few taps of my iPad controller screen.

For many internet radio stations, Roon identifies the artist and title of the track being currently played by the station via Roon's Live Radio function. Whether Roon can show this information or not depends largely on the station itself, as I understand it. Anyway, if the information is available, just touch/click on that information near the bottom of your screen. A new screen will open also showing the name of the album that track is "On." Touch the title of the album and Roon will take you to the album containing that track either within your library or in Qobuz or Tidal. You can then immediately play the high quality version of that track (it's highlighted by Roon within the listed tracks on the album). Or, you can immediately add that track or the entire album to your Roon library.

This is slick for audiophiles who wish they could hear that interesting new track in CD or hi-res quality instead or low-res internet radio quality. It's also slick for music lovers who want to add new interesting music to their personal library when they hear it for the first time on an internet radio station.

Just so there is no misunderstanding, if you are not familiar with Roon: Your Roon library consists of a seamless integration of the albums you own (those you converted to music files from CDs or purchased and downloaded) and those you have rights to access via your subscription to Tidal and/or Qobuz. Once you pay for a Roon license and a Tidal and/or Qobuz subscription, there is no further payment needed to include any albums from Tidal or Qobuz in your Roon library. You merely click on the "Add to Library" button in Roon and Roon instantly adds that Qobuz or Tidal album to your library.

When you browse your Roon library, any Qobuz or Tidal albums you have thus added will appear seamlessly intermingled with the albums you own, displayed in the order you choose. If you have so specified in your settings, the album thumbnail images will also show whether that album is from Qobuz or Tidal and specify the resolution as CD, MQA, or some specific type of hi-res, such as "24/96."

Your Roon library can thus get as large as you choose with the method I described (adding albums found via Roon's Live Radio function) without paying anything beyond the basic Roon, Qobuz, and Tidal subscriptions. And since you aren't downloading the Tidal or Qobuz content to your local computer network, just streaming the content from the internet, adding a Tidal or Qobuz album to your Roon library takes only a second or two.
 

tmallin

WBF Technical Expert
May 19, 2010
549
124
455
68
Chicagoland
Another sonic tweak to the sound of Roon into my Lumin X1: At least in my system, in the DSP engine of Roon, setting the DSD to PCM filter to unfiltered (instead of the Recommended 30 kHz or any other available value) results in a significant further improvement in sound quality.

I was hesitant to try this at first, given the warning in the setting and Roon documentation about it. But since I'm not converting DSD to PCM in Roon and since my Lumin X1 accepts native DSD 512, no such filtering should be necessary, right? I got brave and tried it, after trying the "permissive" 50 kHz filter and finding that to sound better than the recommended 30 kHz filter.

I'm not sure why this filter setting should be audible at all in my system since the signal path does not show any DSD to PCM conversion step within Roon or within the Lumin. But, in any event, in the specific context of my system, setting the Roon DSD to PCM filter to unfiltered sounds significantly better yet and seems safe. Nothing is overheating and there are no sonic problems or digital hiccups at all.
 

tmallin

WBF Technical Expert
May 19, 2010
549
124
455
68
Chicagoland
The combination of upsampling/resampling everything via Roon's DSP engine to DSD 512, Leedh Volume processing by the Lumin X1, and the elimination of the DSD to PCM filtration in Roon has enabled my system to push past some threshold into a realism I've never before achieved. On much program material, there is an absence of artifacts and a see-through realism which allow me to suspend disbelief to an extent never before possible. This is even true for much low-bit-rate internet radio material.
 
  • Like
Reactions: kyhf5168

tmallin

WBF Technical Expert
May 19, 2010
549
124
455
68
Chicagoland
One further significant sonic tweak I just discovered for my system running Roon software on my Roon Nucleus+ feeding my Lumin X1: Turn off the MinimServer which ordinarily would serve to feed my music files to the Lumin X1 via my home network and the Lumin App. The result is significantly more solid imaging (especially in the center) combined with considerable expansion of front-to-back depth.

Why this should be so in my system is somewhat puzzling. The MinimServer program runs only on my desktop computer and accesses a copy of my music files which resides on one of the solid-state drives of that machine. Roon pulls my music files from a USB stick plugged directly into one of the USB ports on the back of my Nucleus+. The MinimServer program and its associated music files only are used if I'm directly using the Lumin App installled on my Lumin X1. The MinimServer program should not be involved at all in the playback of music via Roon.

But perhaps the connection is that the Lumin App, which is controlling the system volume and using the new Leedh DSP volume processor, and maybe the Lumin X1 itself, is relieved of processing overhead when the MinimServer program is turned off. That's the only possible explanation I can come up with. The resulting sonic improvement is not difficult to discern in my system; it is significant.
 

tmallin

WBF Technical Expert
May 19, 2010
549
124
455
68
Chicagoland
And round and round in circles we (or at least I) go. . . .

I don't mean to declare any of the above extolling of Roon's upsampling/resampling (to high-res PCM or, especially, DSD) a case of mistaken first opinion.

But if you disagree and find that native resolution for any program material sounds overall more natural, I won't argue with you. I may have incorporated too many changes too fast and am now just sorting out the effects.

Perhaps it's the new Leedh DSP volume controller that Lumin has added. But with the addition of this Leedh DSP volume, and running Roon through my Lumin X1, listening with native resolution (Roon's DSP engine totally disabled) now usually sounds overall the most natural.

Yes, listening without resampling to DSD 512 via Roon gives up a very pleasing bit of openness and space. Cymbals, in particular, sound airier and more spatially expansive with the resampling.

But resampling, as it always did in my past pre-Roon experience, also sounds a bit overall brighter and less weighty. It's as if the entire tonal center of the presentation shifts higher up in frequency and also elevates a bit higher in terms of where I perceive the stage. That last bit is odd since my Gradient 1.4 speakers have a coaxial midrange/tweeter arrangement, so it does not seem that increasing the relative amount of treble should raise the perceived height of images, but it does seem to do a bit of that.

But more importantly, resampling reduces the gravitas, weight, and thrust of the presentation and overall lessens the tonal naturalness compared to what I regard as a natural tonal balance from acoustic instruments. If you value tonal naturalness, uber alles, you may find that the added openness and space which resampling offers to not be worth the trade-off.

Let me quickly add that this tonality/space trade-off is much less apparent with Roon's DSP engine than it has been with other resampling I've listened to, including the Lumin App's own implementation of resampling to high-res PCM or DSD. With Roon's implementation, I think it really is much more a matter of taste, rather than clearly better or worse.

Roon's resampling sounds different, for sure, but whether it sounds better (in a natural tonality way) is probably a matter of taste. Those not familiar with the sound of live unamplified acoustic instruments in a favorable indoor space may find it to be no-contest at all--DSP resampling wins hands down because of its apparently larger, more open presentation and enhanced sense of recorded detail without "digital sounding" artifacts. But if you know the sound of the real thing and want recordings of unamplified acoustic instruments to sound closer to that ideal concert-hall sound, then native resolution is what you may find to sound better overall.

Your choice--resampling or no resampling--and Roon gives you that choice very easily with a simple enabling/disabling of the DSP engine. Open the volume slider, touch on DSP, then slide the Sample Rate Conversion on/off slider to enable or disable the resampling. That takes less than 10 seconds to do.
 

tmallin

WBF Technical Expert
May 19, 2010
549
124
455
68
Chicagoland
Live Radio in Roon Resamples Stations to 24 Bits

You may not have noticed, but when one examines the signal quality panel of Live Radio stations in Roon, most all show that the signal is 24 bits in terms of bit depth. This is so even though I have all DSP functions disabled, specifically upsampling/resampling. It is my understanding that most internet radio station broadcasts are natively 16 bits.

I thus wondered why the Live Radio stations show up as 24 bits when most are only 16 bit transmissions. I wondered whether this was an error in the signal quality display function for Live Radio or whether there was some behind-the-scenes resampling taking place. I posted this question in the Roon Community forums.

Certainly the sound of many stations through Roon’s Live Radio function differs from the sound of the same station through, for example, Lumin’s radio function. Lumin’s radio function displays 16 bits as the bit depth for most all internet radio stations which, as I understand it, is the native bit depth of most internet radio transmissions.

I’m not saying that Roon’s signal is better or worse in sound quality, but it’s hard to deny that the sound quality differs between the Roon and Lumin versions of the same station even when I’m reasonably sure both are playing the same stream from the station. Compare, just for one example, the 64 kbps AAC signal of KCSM via Lumin and via Roon.

Generally, across all stations, the Roon sound seems clearer, less "congested," and more open and larger in soundstage presentation, but with a tonal balance a bit skewed toward the treble--less weighty, in other words and a bit brighter. The Lumin internet radio station sound has imaging which is better focused with more natural tonality and a less "tense" sound, although the presentation is smaller and less open sounding in terms of staging and more "congested."

I would say that Roons upsampling/resampling very generally has these same sorts of sonic effects when voluntarily applied to any signal listened to via Roon's DSP engine. This is so regardless of the native signal sampling or bit depth. The more extreme the upsampling/resampling on undertakes via Roon, the larger the audible effects. Whether you think the upsampling/resampling sounds "better" or not is, I think, a matter of sonic taste and priorities. But there is little doubt that upsampling/resampling via Roon (or via the Lumin for that matter) sounds different.

I find no way to change the bit depth of Roon Live Radio signals from 24 bit to 16 bit. I would like the option to listen to Live Radio signals in their native bit depth which, as I said, to my understanding is usually 16 bits. I asked if a function be added to allow overriding the resampling of internet radio stations from16 bit to 24 bit.

Here is the response I received from a Roon staffer:

Once audio has undergone lossy encoding, it no longer has an inherent bit depth. The encoded bits can be thought of as a mathematical description of how to reconstruct an approximation of the waveform that went into the encoder. The decoder usually calculates the reconstruction using floating point or integer math with at least 24 bits of precision. We chose to output 24-bit PCM in order to avoid introducing unnecessary dither 2 to the decoded audio. Dither is basically a necessity when dropping audio down to 16 bits per sample from a higher bit depth, but it’s problematic when talking about lossy decoders:

If a lossy file was created from a 16/44 source like a CD, the audio already had dither applied to it as part of the mastering process. Decoding to 16 bits per sample would add additional dither.

If a lossy file is the product of a more modern mastering process like Mastered for iTunes 4, it’s likely that the original source for the encoding was undithered 24+ bit audio. In that case, decoding that file to 16 bits per sample would introduce dither where there was none before.

In addition to improving sound quality for lossy files, this change also simplifies some of the associated code, making everything a little more efficient (and less work to maintain).

These days, I generally prefer not to upsample/resample any program material of CD quality or better. For low-resolution internet radio signals, however, I have to say that my preference is not so clear. That's why I would prefer a choice within Roon. I can always switch back and forth between the Lumin and Roon versions of the station's signal, but that is not nearly as convenient as it would be if Roon offered a toggle between the native and resampled versions of the station's sound.
 

About us

  • What’s Best Forum is THE forum for high end audio, product reviews, advice and sharing experiences on the best of everything else. A place where audiophiles and audio companies discuss existing and new audio products, music servers, music streamers and computer audio, digital to audio convertors (DACS), turntables, phono stages, cartridges, reel to reel, speakers, headphones, tube amplifiers and solid state amplification. Founded in 2010 What's Best Forum invites intelligent and courteous people of all interests and backgrounds to describe and discuss the best of everything. From beginners to life-long hobbyists to industry professionals we enjoy learning about new things and meeting new people and participating in spirited debates.

Quick Navigation

User Menu

Steve Williams
Site Founder | Site Owner | Administrator
Ron Resnick
Site Co-Owner | Administrator
Julian (The Fixer)
Website Build | Marketing Managersing