SQ Comparison of 3 streamers

@mdalton  As an end user, you can still judge whether you can hear the effect of jitter. The audible noise floor threshold is around –110 dB. For a 10 ps jitter from a high-end DAC, this is equivalent to approximately –118 dB at 20 kHz (=f)

20log⁡10(2π⋅f⋅jitter) (jitter in ps)

and is likely completely inaudible. If the jitter is around or above 25 ps, its effect could become perceptible, particularly on a very high-end, sensitive system.

Jitter is one thing, but as both you and I have pointed out, electrical noise is equally important. High-end gear including the power supply, is usually measured in  the level of microvolts (µV). For example, the T8 demonstrates outstanding measurements down to 30 µV within the chassis (not sure if in full load?).  I wish all independent reviewers would expand their measurements to include this area.

Other measurements, such as SNR, THD+N, and dynamic range, are more standard, and I generally refer to manufacturer-published data. ASR usually provides these measurements for verification, and I have periodically found them to be consistent with the manufacturer specs. If such data is missing for gear you are interested in, it might be a lost opportunity for you.

Ok, last nerdy post, I promise.  I looked back at some incomplete signal to noise ratio numbers included in Allen’s measurements, and they’re pretty cool too.  So, for the Audioquest Dragonfly hooked up to a noisy PC, SNR was 94 db, but when hooked up to Volumio, was 104.  So the PC added 10 db more noise than the Rivo, which is definitely audible.  Now let’s compare that to an Antipodes Oladra, which cost £25k when it was reviewed.  The SNR number for the AQ was exactly the same, 104.  Interestingly, Allen measured these numbers for the Oladra with the iFi as well, and the SNR was 110 for both the noisy PC and the Oladra.  So once again, the DAC matters; in this case, the iFi, which doesn’t handle jitter well, filters out other noise extremely well!  Finally, Allen also measured SNR for the Lumin U2x with the AQ, and the SNR was 102.5, which is lower than the Volumio.  Really interesting stuff, and it’s just one reason why I have been preaching to people that they do not need to spend big $ to get state of the art performance.

our notes crossed.  Yes, I’ve found some of ASR’s measurements helpful, but unless I’m missing something, I don’t think they typically measure/evaluate streamers.  Part of the reason I suspect is that Amir thinks streamers are basically irrelevant, and that it’s a waste of time and money to spend more than what a Raspberry Pi costs unless you want something a little prettier.  I disagree with this view, but I get it.  Amir believes that a well-engineered dac is not susceptible to incoming jitter, and that good engineering also requires excellent noise filtering (a la the iFi dac).  Again, I get it, but I think that’s too reductive.  I think people should be allowed and encouraged to buy whatever they like, including non-oversampling dacs that measure poorly and are susceptible to incoming jitter.  

My one non-negotiable though is that we should all have as much info as possible to help inform our decisions, and I really abhor the mystical approach where people claim everything matters.  Everything doesn’t matter, in certain circumstances, due to the diversity of our systems.  As we’ve seen, som sacs need low-jitter streamers, some don’t.  

And I like that you’re trying to figure out why you’re hearing a difference between apps that, in theory, should sound the same if they’re just providing identical bit perfect streams on the same piece of hardware.  There has to be an engineering explanation for that, and I hope you provide any additional info you can glean about it.  Have you thought about asking Volumio directly?

@jrareform 
I can offer a comparison of the WiiM Ultra vs Holo Red outputting via USB to a Singxer SU6 into a Pontus 15th. 

The Ultra sounds a bit recessed. Everything is a little mushed together. The stage isn’t as high nor as deep. The transients and seperation are not clearly presented.

The Red sounds more dynamic, more detail, taller stage, more depth of stage. Transients and details as well as tonal accuracy is much better.
 

However the WiiM Ultra is warmer and tube like in the way that tubes kind of add a little body/thickness to the music or seem to harmonize things. The Red is more finely detailed which can be considered an effect of a good tube amp but lacks the warmth. Monet vs Rembrandt. 

Right now I’m running everything through a tube pre known for its clinical character and into a Buckeye Hypex. It will be interesting to compare again once I connect an Orchard Audio Starkrimson as while I believe it’s still Hypex based the implementation with more caps lends itself to a warmer more lush and musical presentation. So far I’ve only tried it with the Ultra and not the Red. I’m anticipating audio nirvana once I connect the Red and Starkrimson. I’ll try again to eliminate the SU6 but have a feeling it will continue to add a necessary flourish for a more natural effect as it does now. To me, digital can feel overly clinical and cool even with decent mid-fi gear. Crazy what this stuff costs to get into once you develop the ear for it. 
 

Speakers are Wharfedale Linton 85th and so far they’ve been great- musical but able to reveal enough detail as my system grows. 
 

edit: Listening again I have to add something: the Ultra is a little distorted in the highs compared to the Red. Otherwise I would probably be satisfied with it for streamer duty. But as such it’s a bit rough or crunchy to my ears. I loathe roughness in high notes but much more tolerant in the mids of distortion. Up top it is too fatiguing to me. 

My theory on differences in sound quality between Qobuz Connect and a streamer native app - it’s in the processing path the signal takes. Native streamer app most likely includes some DSP that is bypassed when using Qobuz connect. 
When comparing Roon to native app or Qobuz connect, again the DSP that takes place in Roon core influences the sound quality. And the streamer native app is bypassed, either fully or partially. 
It’s bit perfect in each case.