Roon Sound Quality vs. Pure Music/iTunes

Roon Software Discussion
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I’m running Roon trial, with only a few days to go.

We had the chance to do some careful testing last evening, and came to a conclusion that we had already suspected from casual listening: Roon’s sound quality is simply not as good as our usual setup, PureMusic over iTunes.

Please note: This post is not to bash Roon’s sound quality. I enjoy Roon for the ‘relationships’ and exploration capabilities. I’ve already found a number of ‘new’ artists. What I’d like to do is to have Roon sound more like our usual setup, and I am looking for ways to do that.

Actually, in our setup it wasn’t even close. There were clear and obvious differences in SQ, taking only seconds to discern. It caused my wife to say, “So, Roon is for when we’re in the other room,” as we often listen from the kitchen and dinette while making dinner. Serious listening is in the sweet spot in the living room.

This leads me to the question, which is, “How can I enjoy the benefits of Roon’s iTunes library and Tidal integration without taking such a hit on sound quality?” Perhaps I have to take the bad with the good, as Roon’s strength is ‘relationships.’

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More info:

We have what we would call a resolving system. Mojo Audio Mac Mini with Joule V power supply; external FW800 HDD; PS Audio Directstream DAC running Yale OS; Rowland Continuum S2 integrated amp; Magnepan 3.7 speakers; Transparent Audio USB and interconnects; Stillpoints; Shunyata Triton Hydra and Shunyata Anaconda PCs; Room treatments galore.

PureMusic is running in Exclusive Integer mode, upsampling to 192 except on DSD, which passes at that DSD’s resolution. So, in most cases, I’m upsampling Redbook 44.1 to 192.

We chose one of our favorite testing albums, Graceland. (Later we tested with others; same results.)

We first played tracks from the album ‘Graceland’ using Roon to pull bits off of Tidal’s version. We then quit Roon and flipped over to PureMusic/iTunes to play a WAV version ripped from CD. Winner: PM/iTunes, by a wide margin.

What was most interesting, though: Using Roon, we played the track “Under African Skies” from the WAV rip in our library, then flipped to PM/iTunes and played the exact same track from the library. Winner: PM/iTunes, again by a wide margin.

While the Roon version wasn’t bad, the PM/iTunes presentation was obviously more clear, with deeper and wider soundstage, better bass slam, resolution of individual instruments… everything was just more ballsy and present. Very engaging. And again, an obvious difference.

This is a disappointment for me; I’d love to hear some older or unexplored recordings, but want to hear all of the music.

Now, I know that we say “bits are bits.” Yet, I’ve got Roon running in CoreAudio Exclusive Mode, so it’s using the best possible path, as I understand it. But if it’s true that bits are bits, I find it weird that one can play the exact same track from an album – once through Roon and once through PM/iTunes – and get astonishing different results. Either upsampling in PM is making a difference, or PM’s processing simply results in a better sound.

I cannot run Roon through PureMusic, unfortunately. Well, I can, but PureMusic runs in “passthrough” mode for anything other than iTunes. It would be interesting to test that combination, but in theory, PureMusic doesn’t touch the bitstream as it passes through, so I’d expect that in that case, Roon == PureMusic Passthrough == less than optimum SQ.

So, sorry for the long post, but I’d love to get some input on what I’m hearing. Is there any way to get Roon’s SQ up to the level I’d expect? Or, should I consider Roon to be good at exploration, but not quite suitable for the most discerning listening sessions? Might HQ integration make a difference? Any theories on why bits-are-not-bits in this case?

Thanks,
Rob

1 Like
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I’m not familiar with Puremusic, but I suspect that the upsampling and filters it uses are taking a load off your DAC and/or may be better than the filters in your DAC. So you are sort of comparing apples to oranges since Roon is simply passing a bit perfect stream to your DAC but Puremusic is doing additional DSP.

A comparison of HQP and Puremusic would be useful, but I wasn’t able to readily find one online.

HQP integration is coming in the short term. The HQP trial I had some months ago favourably impressed me and I’ve just purchased a licence.

I would definitely recommend comparing Roon/HQP to iTunes/Puremusic and would be interested in what you found.

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Thanks, @andybob

Makes sense. FWIW, I don’t use ‘filters’ on PureMusic, though I am upsampling. No DSP settings that I’m aware of. Perhaps it’s just something in the PM engine that makes the difference.

I plan on trying HQP once integration is available. Is there a timeframe on that?

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A timeframe hasn’t been announced but Brian was teasing us with happysnaps 11 days ago.

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Hi Rob,

I think external [from the DAC] upsampling can have a huge impact on the sound quality and gives the user choice.

Would it be possible for you to play some native 192K tracks, and make the same comparisons?

I’m not so familiar with PureMusic, but doing so should mean it just passes though the digital audio without any extra processing … which should result in your DAC being fed the same signal when being driven from the two signal paths.

I’m really curious to read about what if any differences there are.

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As far as I know Roon is engineered to provide the best possible audio stream to endpoints and as such it passes through the source untouched…nothing taken away and nothing added. If you find you prefer the sound from other players it’s because you like what they add or take away, not because “Roon’s strength is relationships”.

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@Carl

Yes, I’d like to do more testing as soon as possible. I won’t have access to my system until the weekend, but will post results here when I can.

I like the idea of sending 192 to compare. Another test would be to simply disable up sampling to see if there is still a difference in SQ. I would imagine that PM/iTunes “untouched” might be similar to Roon’s delivery. If not, then perhaps PM is adding something.

@audiomuze

I like Roon for a number of reasons. It’s just that the SQ is not currently what I’m accustomed to, and that’s what matters most to me.

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That’s fine, so long as you don’t confuse your likes with fidelity.

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That’s fine, so long as you don’t confuse your likes with fidelity.

+1. He’s running a TOTL DAC and really shouldn’t be applying external up-sampling and/or filters, IMO.

Frankly, I’ve done similar comparisons with Audirvana+ and Roon into my Mid-Fi DAC (Rega) + headphone rig; I think Roon sounds fantastic and does a really good job of stable delivery of bits.

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I have often wondered why people buy a really good digital system then spend loads of money and time trying to make it sound like a vinyl/tape system. isn’t it easier just to buy a turntable or reel to reel ?

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Just to make sure we’re all on the same wavelength, all digital audio involves filtering. At the analog to digital stage an anti-aliasing filter is used and at the digital to analog stage a reconstruction filter is used. The reconstruction filter is a low pass filter and in Redbook it has to approximate a steep “brick wall” shape between 20kHz and 22kHz. Although it only takes away inaudible high frequencies, all the signal passes through the reconstruction filter and can be affected by it.

Designing a steep brick wall filter is problematic. It can introduce artifacts seen on oscilloscopes as ringing or pre-ringing, meaning minor oscillations around transients. Recordings of solo piano are said to be useful when listening for such artifacts. Some people like the sound of such artifacts, but most hi-fi enthusiasts would prefer to do without them.

The benefit of upsampling is that it provides more headroom for better reconstruction filtering using gentler slopes that do not create unwanted artifacts. All upsamplers will apply such filters, there is no point to upsampling without doing so.

Since electronics is built of compromises there are choices to be made in such filters, including whether to prioritise minimising group delay or ringing associated with transients. Many DACs now offer a choice of filters for users to try.

So filtering is necessary and upsampling enables a broader choice of filters. None of those filters are designed to add or take away anything (except inaudible high frequencies) but each of them will introduce different types of artifacts or distortion compared to the original waveform. Our job is to judge between such compromises.

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@andybob

Thanks for the informative post. It’s good to see someone willing to take the time to elucidate, rather than questioning a person’s preferences and decisions.

I don’t profess to know much all the ins and outs of digital playback; learning every day, which is also how I like it.

When I first set this rig up, I tried a few combinations and then settled in with what sounded best to my ears. Now I’m looking forward to getting back to the rig to try different settings and possibilities based on what I’ve read here, and I expect more favorable results.

I’ve enjoyed the convenience of digital playback, having relegated my CD collection to the closet. Vinyl? Not for me; I’ve been there. Tape? No thanks. Roon brings the best of streaming combined seamlessly with my library. Sometimes one just needs guidance as to the best options.

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Between DSD upsampling with HQP and fidelity, you can keep fidelity.

Taking a relatively low resolution signal such as Redbook audio and carefully interpolating samples between the existing samples to increase the effective resolution is the kind of “distortion” I can get behind. I imagine a crude drawing on graph paper with medium sized blocks transposed onto another piece of graph paper with much smaller blocks.

Anyway, the purpose is not to make the original data sound “better”, but rather to feed your DAC a signal that it can convert optimally. Which leads to the other point that makes this discussion moot, in my opinion. All but a very small number of DAC’s upsample lower resolution signals internally anyway. Digital filtering is far less invasive with higher resolution data. The popular ESS Sabre chip (used in the Auralic Vega and many other premium DACs) also converts all PCM to a DSD-like SDM signal before conversion to analog. To achieve state of the art performance without this kind of DSP is possible, but it’s difficult and expensive and I have no idea whether the end result is any better for having remained “pure”.

I wonder how many people who prefer their data stream to remain bit-perfect realize that it’s being molested inside the DAC before being converted to analog? :grinning: The developer of HQP posits that it is better to handle the DSP in the server, bypassing the DSP in the DAC, which has a tiny fraction of the processing power found in a modern server. Plus, using the computer, the DSP is configurable and upgradable. Rob_Hanson has enjoyed the results with PureMusic and many of us have had a positive experience with HQP, which is why there is so much interest in Roon/HQP integration.

Purity of the signal seems like an obviously desirable ideal, but I feel that view is oversimplified. Upsampling externally in the server generally bypasses the internal processing the DAC, yielding better sound because the DAC is doing less harm to the signal.

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Agree with that Keith, but I don’t see upsampling and fidelity as necessarily opposed. Upsampling is digital signal processing usually intended to get closer to the signal, which is how I view fidelity.

Also I have to confess to a fondness for tape. A friend came over to dinner last Saturday and we had a great time listening to “Axis Bold as Love” on tape. Sure there was hiss and I’ve no doubt digital is higher fidelity, but it was enormous fun.

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I completely agree.

I was addressing the widely held opinion anything other than “bit-perfect” playback is a distortion or coloration of the sound.

That idea makes complete sense superficially, so I was trying suggest that there’s more to all of that than meets the eye.

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IMHO converting 44.1 to 192 is up sampling that does not maintain ‘fidelity’ of the original bits. A 4x integer up-sample from 44.1 to 176.4 would be better. Not sure I have seen this distinction in the comments above.

I’m not suggesting a user couldn’t prefer a non integer conversion.

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6 posts were split to a new topic: Digital Audio - Frequency and Time Domain Requirements for Audio Reproduction

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I suspect everyone here knows this.

What is sometimes missing from the PC CPU vs. DSP in the DAC discussion is that higher end DACs usually implement their filters within FPGAs, which are software upgradable, prior to sending to the DAC.

In this environment, I am of the opinion that all of that extra CPU horsepower does little more than generate electrical noise, because the FPGAs and ASICs are, by design, “fast enough” for the task at hand.

I realize that this puts the customer at the mercy of the DAC vendor to upgrade/update filters via a software update, but I personally would rather leave that task to people who really know what they are doing (i.e. the DAC vendor), rather than making a bunch of incremental adjustments to things like pre-ringing, slope, et al., and then relying on sighted comparisons. If you really enjoy that kind of tweaking & experimenting, then by all means, it’s a hobby and have fun.

My Rega DAC has 5x2 sets of filters that may be selected from the front panel and the differences are really, really subtle, even listening with resolving headphones.

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The use of FPGAs in DACs is relatively new, but is certainly catching on and your points are entirely reasonable as FPGAs turn this discussion on its head.

However, the salient point in my opinion is that nearly all of us are listening to altered data streams. That’s a fact that the “bit-perfect” advocates seem to dispute. But once you accept that fact, then different methods of upsampling (DAC chip, FPGA, HQP, JRiver, foobar, PureMusic) will sound different. I prefer to experiment (especially since the software can be tried at no cost) rather than decide that one method is likely to be best based on any objective theory - such as “all of that extra CPU horsepower does little more than generate electrical noise”.

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I am in agreement with you.

But let me state this: in my armchair experience, what seems to provide the biggest impact with respect to improving sound quality, all things being at a certain quality level to begin with, is mitigating electrical noise.

This is why I am a believer in using purpose built rendering machines at the DAC and separating the CPU intensive work into a machine somewhere else on the network (optical or wireless isolated, if I’m being OCD).

Of course, this fits nicely with the RoonServer / HQP processing -> Roon Remote -> DAC model.