HDX vs. UServe - via nDAC and via NDX; are we failing by the source components?

Posted by: aysil on 09 April 2011

NDX is out, and there is a lot of excitement around its sound and different comparisons with similar devices, with nDAC, different PS, etc. Are we thereby overlooking another important question – the importance of the source component?

Part one: different source components via nDAC

When I had, in an earlier post, reported big sound quality differences between HDX and UServe through my earlier DAC, some members asked if I hear the same differences through my nDAC. Some suggested the differences would diminish through nDAC. I was also very curious.

One by one, I connected HDX and UServe to the same input of nDAC with the same digital cable and listened to different kinds of music from the rips I had made to the on-board hard drives of both devices. (Both are non-ssd versions) The results were identical to my previous findings using my previous dac: “UnitiServe sounds more nervous, a bit more rough, and the micro-dynamics more flat (in comparison to HDX). The HDX has a more relaxed presentation, more resolved, better flow, and more precise rhythm.” I can add further: HDX has deeper soundstage and more correct tone colors.

I don’t know why some members on this forum did not hear the difference in their own system. (It is not a negligible one. My friend accompanying me during the auditioning did not even believe we were playing the same track!) Of course, in a more revealing system the differences would be augmented. My Kondo Souga amp is definitely an extremely revealing amp; annoyingly revealing at times! I hear the different positioning angles of microphones, and thereby sometimes “see” a distorted soundstage or a bent forward piano or things like that. However, any system from the different Naim ranges would also have, to varying degrees, the resolution to convey this kind of differences. (Edit: it turned out later in this thread that those members who have compared these two devices had used a NAS and they were playing the same file on the NAS, contrary to my case. See later on this thread)

I am not writing these to discredit UServe. Its weaknesses are only in comparison to HDX. UServe is probably one of the best sources in its own price category. I wish I could compare it to CD5XS, which is almost the same price. I asked our distributor, but it was not in stock at that time. The only thing I could find at hand for comparison was a less than £1k CD player from a neighbor. It was definitely much worse. Compared to UServe, it had much less detail, and a blurred and muddy presentation.

CONCLUSION 1:

Naim DAC’s “buffering/re-clocking architecture” is Naim’s ingenious solution for the task of GETTING THE BEST OUT OF A DIGITAL SOURCE. It is by no means there to disguise the quality differences of source components, nor does it make up for the weaknesses of inferior sources! Unfortunately, we just cannot escape the issue of the quality of the source component.

Part two: different source components via NDX

What happens when NDX comes into the picture and we use UPnP streaming instead of the S/PDIF connection? Does the characteristic of the source component play as important a role? (With source component, I mean the component which comes before the NDX, for reasons I will explain below) There are already some test reports online, which compare different source components connected to Linn DS devices and describe the differences. In fact, in one of them, HDX scores much better than RipNAS, for example. I wanted to reach my own conclusions. Taking HDX and UServe as two examples of different computer audio source components, I connected both to the modem with the same length, brand of CAT6 cable and auditioned them through the UPnP input of NDX.

First, they both sound quite different through UPnP. UPnP transfer and S/PDIF transfer have very different sound characteristics. I don’t have a clear winner yet; they have different strengths and weaknesses. (This should be the topic of another post.) However, the difference between HDX and UServe remains! In fact, the difference is much bigger because UPnP is the more detailed (and revealing) method of digital transfer. The characteristics of the two source components are exactly the same as above in the previous comparison. It can be quite disappointing to switch from HDX to UServe. The beautiful silky textures of string instruments from HDX give way to a somewhat scratchy presentation from UServe, and the nicely swinging body of the clarinetist from HDX gives way to a somewhat more stiff musician body from UServe.

I must say again: these remarks should not discredit UServe for those who are enjoying this device in their Uniti systems. The description is only relative to HDX, and in regard to HDD versions. The only conclusion to draw is that different computer sources may sound significantly different. (HDX and UServe are, in principle, dedicated computers.)

One interesting note: the difference was consistent whichever server I used to stream the data, HDX server, UServe server, or Asset server on my laptop. That means, for example: when I used the UServe as server, the sound was better streaming data from HDX’ hard disk drive than streaming data from its own hard disk drive. (Edit: this actually coincides with the experience of some members who have compared the devices when playing the same file from the same location and did not find a major difference. See later on this thread)

I cannot know to what extent the above-described differences btw the two devices stem from the actual ripping and to what extent they occur during the process of reading the data from the drives. Many would assume that if the ripping engine and algorithms of the HDX and UnitiServe are the same, the data on the drives should be the same. However, I don’t want to rule out the effect of the different cd-drives of these devices on the supposedly same ripping engines. One interesting test would be to change the save location of the rips and save the rips of both devices to a common third location on the network. (I don’t have a NAS, so this could be a folder in my laptop computer.) I will try to do this test during the next weeks and report to you. It will be interesting to see if the rips from these two devices will sound different when saved to the same third location, and the sonic differences between these rips and the rips saved directly onto the on-board drives.

CONCLUSION 2:

During the online chat on NDX, Gary Crocker called the NDX a “source component”. I doubt if this is the correct term. The digital audio data is processed in the inner topology of a computer source before being transferred to NDX. Therefore, we should call NDX, like other “renderers,” an intermediary component, where the computer IS the source component.

If two computer sources from the same manufacturer can sound so different, I guess different computers, different NAS, even different usb sticks sound considerably different. In fact, I start to believe that, with regard to computer audio, we are in a similar phase to the early 1980’s with regard to cd-playback, when most people believed cd-transports have no influence on sound quality, as “they were merely transferring the ones and zeros to the dac”!

We will soon find out, how the power supply of our computer, or the material of the outer case, or the brand of the hard drive, or the quality of the inner cabling, or any element of the topology of our computer, or even the CAT cable we use to connect to the network influences the sound. When I search back on this forum, I actually find many posts that point at such influences. They have not been the focus of attention of the majority. As the quality of the “renderer” components rise, such aspects will become more audible.

There are some members on this forum, like Tog, who regularly advise that any worry about the influence of a factor on the sound would make sense only if it makes a considerable impact in the current level of the whole set-up, and that we should be able to sit back and simply enjoy the music! I find such warnings very valuable, because audiophiles do tend to forget this basic fact and get lost in worries and details. However, we cannot escape such worries altogether as it is this quest for better sound that brings us together in this forum. Total piece of the mind exists only in Heaven!

Posted on: 11 April 2011 by aysil

Originally Posted by AMA:

aysil,

1)I have compared UnityServe against Logitech Transporter -- both as digital transporters through nDAC and I could not find any difference. Both were sounding very good and indistinguishable in sonic character. At the same time the difference between them and other digital sources was not subtle (there were various USB/SPDIF transports and CD/DVD transports). While doing a demo I have arranged a proper setup for both sources: both gears powerlined, both on a separate spur away from the amps, same coax cable, same data storage. I switched the inputs many times on various tracks for 3 days (!!!). I failed to pick up any meaningful difference. Possibly my system is less revealing than yours, possibly my hearing is not that good (though I'm usually much more critical to SQ than many others). It does not diminish your finding though. It might be that HDX is so much superior to both UnityServe and Transporter that it propagates its quality through re-clocking nDAC -- and this would definitely be a good news (if one can close the eyes on Allen's experience).

2) Your experience with uPnP broadcasting is very queer. I have pulled various bitstreams to nDAC with a number of ways but it always sounds the same -- with a full accordance to a sheer logic. Are you sure you have proper/equivalent/healthy network setup?

3) Did Linn KDS player ever come to your scope of interest?

AMA,

1) I really did not understand, why you should have found differences between UServe and LT. Maybe, they are really similar. I want to ask you the same question I just asked Allen: Did you compare them as they were playing files from the same location? Maybe this was the reason you could not detect substantial differences. I suspect that save location plays a role, but I don't want to jump to conclusions before testing this empirically. Otherwise, you say that you heard big differences between these two sources and other digital sources to nDAC, which confirms that differences btw sources are possible via nDAC. And yes, I must admit that according to my taste and in my system, HDX is superior to UServe.

2) My experience with UPnP streaming is NOT queer. I don't believe in "sheer logic" but in thorough research and empirical testing. I am very sure my network setup was totally fair to both sources. I did not understand how you pulled streams to nDAC. To my knowledge, it is not a streaming client.

3) Yes, in fact, I auditioned the KDS at home, thanks to a kind distributor here. It was obviously not a totally bad product, but I don't want to comment on how it compares in specific aspects. However, Linn systems are out of the question for me for the sole reason that they don't have S/PDIF output. They don't allow free choice of DAC. The DAC, especially the analogue output section of a DAC gives the decisive footprint to the sound of a system, and everybody should be free to choose this freely. You can not alter this later through amplifiers. I prefer to keep my existing dac in my system.

Posted on: 11 April 2011 by Mr Underhill

Originally Posted by aysil:

3) Yes, in fact, I auditioned the KDS at home, thanks to a kind distributor here. It was obviously not a totally bad product, but I don't want to comment on how it compares. ....

I'd be interested!

Posted on: 11 April 2011 by AMA

Aysil, in my system the KDS bass was lightweight and less punchy than nDAC/XPS.

How was the KDS bass comparing to nDAC or Kondo DAC in your tests?

BTW the new Linn ADS/2 is equipped with S/PDIF output.

Posted on: 11 April 2011 by aysil

Originally Posted by Mr Underhill:

...

I'd be interested!

You just wrote you want to spend your time listening to music. Really, every system has its pro's and con's; it's better to just relax and enjoy the music with what you have!

It's been a long time I made this listening and I did not have any other product to compare, other than my cd transport/dac combi, which I think is unbeatable anyway. Having experienced NDX now, I see no reason to look elsewhere for a streaming client which happily also integrates with my existing dac - although its on-board dac is also marvellous.

this thread was not for comparing Linn/Naim stream players!

Posted on: 11 April 2011 by AMA

Originally Posted by aysil:

I did not understand how you pulled streams to nDAC.

I did it with streamers and USB-S/PDIF convertors. I streamed the hi-res files locally and through the network and there was no audible difference in SQ which only means that my home network is definitely transparent to hi-res streaming.

Now, if you found that streaming from HDX and UnityServe through the same network is different when picked up by the same client (NDX in your case)-- this is a very bad news.

It means that UnityServe does not broadcast the bit-perfect image of the NAS-based flacs.

And it also means that using TP and UnityServe I had never got the best of the streaming audio.

Posted on: 11 April 2011 by Mr Underhill

Originally Posted by aysil:

Originally Posted by Mr Underhill:

...

I'd be interested!

You just wrote you want to spend your time listening to music. Really, every system has its pro's and con's; it's better to just relax and enjoy the music with what you have!

this thread was not for comparing Linn/Naim stream players!

Well, I can read and listen! Can't solder and listen.

I can understand your reasons your reasons for not comparing the two.

Posted on: 11 April 2011 by aysil

Originally Posted by AMA:

-- this is a very bad news.

It means that UnityServe does not broadcast the bit-perfect image of the NAS-based flacs.

And it also means that using TP and UnityServe I had never got the best of the streaming audio.

No no! don't jump to conclusions. UServe may in fact be pretty good when streaming from NAS. It all depends on your system configuration; but when you are thinking of an upgrade for your computer sources, I recommend auditioning the NDX.

Posted on: 11 April 2011 by lhau

Totem, That is some nice reply. Shall we suggest to Richard that the forum be divided by "revealing" level so meaningful discussion can be made as ours are "by definition" valueless? We or at least most of us are open to the differences experienced. We are just quite sure that the stated reason "noisy environment leads to noisy/different reading" of harddisk is not the root cause of this from our experience with harddisk devices we know and use everyday. Some of the people did use strong word which might affect how people feel about the core if the message to be appreciated.

Posted on: 12 April 2011 by sondek71

Originally Posted by james n:

Excellent reading Mr Underhill. This is what did it for me with computer audio and led me to the Linn DS route - a fun journey (thanks Allen) but i spent too much time playing ( Memory / SSD drives, Audio players, OSX configuration etc etc ) but not enough time enjoying the results.

I can understand the appeal of a turnkey solutions like the Serve / HDX / NDX which are just plug and play.

James

James,

I totally agree with you: Not enough time to enjoy the results.....

I have now tested more than 20 different software packages now on my Mac Server (Control Points, Media Severs & Media Taggers) and have come to the conculsion that neither software package is what I expect it to be: User-friendly, stable and mature. High-end audio streaming seems to be in its very early stage, and I am (like many of you) an early adopter obviously.

The question I am currently asking myself is: Did I buy equippment to listen to music or to constantly upgrade the different softwares in order to get a user-friendly, stable and mature package? Or shall I just buy one from Naim? Who tells me that this package will meet my expectations? If I read some of the software suggestions made in this forum for the n-Serve app I wonder whether a UnitiServe instead of a Mac Mini Server (with my favorites so far: Bliss, Media Rage and Twonky) will meet the simple expectations many other "consumers" seem to have too.

I know it is hard to make a decent software package (did it the last decade myself with a small company).

But how long will I have to wait for someone else (a solid HW manufacturer) doing it better than many others did? Weeks, months or (what I expect) years? It does also not seem to be a problem of the price tag though......

I have to go now. Listen to just something making me feel better I guess

rock and roll....

Posted on: 12 April 2011 by Tog

Originally Posted by sondek71:

Originally Posted by james n:

I can understand the appeal of a turnkey solutions like the Serve / HDX / NDX which are just plug and play.

James

James,

I totally agree with you: Not enough time to enjoy the results.....

I know it is hard to make a decent software package (did it the last decade myself with a small company).

I have to go now. Listen to just something making me feel better I guess

rock and roll....

There are alternatives

Tog

Posted on: 12 April 2011 by totemphile

Originally Posted by sondek71:

...

But how long will I have to wait for someone else (a solid HW manufacturer) doing it better than many others did? Weeks, months or (what I expect) years?

sondek71 - interesting post, so what are you saying, did you mean to suggest that for the time being you will stick with your MacMini/iTunes/Bliss/Media Rage/Twonky combination because it beats what else is on the market for ease of use, maturity and stability?

Thanks

Posted on: 12 April 2011 by totemphile

Originally Posted by james n:

Totemphile - i'm all for keeping an open mind but i see nothing wrong in questioning Aysils methodology. Whilst he may hear differences, the theory behind these differences is what i question. I know computers and software players make a difference - i've played around with a fair few combinations in the last 3 years and have heard those differences myself.

Hi James,

Fair enough, all I wanted to elude to is that no one here really is in a position to doubt his findings since we have not had the benefit of listening to his system and set up. Rather than for some to come out with strong statements of how these differences are not possible, one way of looking at it might also be that with such a high level system, which he has, you might in fact hear pronounced differences. Are these differences, if they exist, really relevant for most of us here? Probably not because our systems are a lot more simple. Now, if Adam was not able to hear any differences between the UnitiServe, HDX and UQute streaming of a NAS into the nDAC on his 500 system, than that also tells me that I surely do not need to worry about any differences that might exist, since the SuperNait that I currently have will not make them hearable. Nor do I need to worry about it going forward because even if I ever find myself owning a 282/250 in the future, it still won't show. It makes for interesting reading though...

Best

Posted on: 12 April 2011 by totemphile

aysil - btw, thanks for your email reply, much appreciated...

Posted on: 12 April 2011 by sondek71

Originally Posted by Tog:

There are alternatives

Tog

Tog, you must have shares @ Vortexbox..... but I am acutally no looking for another box except if I want to attach a server house with a diesel generator to my flat. to listen to quality music in 2011.

Posted on: 12 April 2011 by sondek71

Originally Posted by totemphile:

Thanks

tp, two options: either stay with what I have and go the upgrade path - stay in contact with several software vendors and keep asking them for ease-of-use and...or on the other hand go the UnitiServe way and keep in touch with only one vendor . time will tell.

Posted on: 12 April 2011 by Tog

Originally Posted by sondek71:

Originally Posted by Tog:

There are alternatives

Tog

Not at all, no shares no financial interests but it's one of those rare things where you are genuinely suprised by the quality of something that does a better job than almost everything else on the market - for free. I think the UnitiServe may develop into something better but at the moment there isn't much to choose between the the two. The fact I can even make the comparison is astounding in itself. Hugely impressed with Andrew at Vortexbox and Jesus at Sonore - like the guys at Naim, true enthusiasts.

My wife won't let me have a diesel powered server shed but luckily my VB server is v low power.

Tog

Posted on: 12 April 2011 by aysil

Originally Posted by totemphile:

Originally Posted by james n:

Hi James,

Best

Hi Totemphile,

It is not exactly true that Allen B was not able to hear the differences I was talking about in his system. We found out that we were actually not comparing the same things. I will write about this in my next post.

In fact, the differences I was talking about were not minor, but quite dramatic. I am pretty sure it would be possible to hear them to various degrees in all Naim range of products. That's why I wanted to share my experience. This is a very informative and interesting forum here in Naim. I learn a lot from all the topics I am reading. It is not possible that we come to the same conclusions even with the same equipment and the same system. Apart from personal taste factors, there may even be some "environmental" issues; For example, my UServe may by chance be picking up some RF from the radio station in the next neighbourhood and messing up with its playback, which could be accounted for by its weaker isolation (just assumptions now) in comparison to HDX, which would not be that of a problem in a more secluded neighbourhood. Whatever; as long as we dig into and challenge each other's findings we all have sth to gain.

It is not about how much money we spend on our system at all. I would be able to set up a fairly good sounding system at any price level. It is about the enthusiasm we share for quality music reproduction, it is about the excitement we feel when the music gets even more graspable in our room. For most of us in this forum, I believe this has become an important priority in life. I had to sell my house to be able to afford my system. The price of the flat I am living in now is less than the price of my music system. This may be rather an extreme case, but I am sure for most of us in this forum, our music system is worth spending more money on than our watch or our car. Isn't that true?

Of course, it is not necessary to be an audiophile in order to enjoy music. In fact, most musicians are not audiophiles; they are happy with their mp3 files - apart from the fact that they are usually partly deaf, being exposed to high volumes all the time!

Posted on: 12 April 2011 by AMA

asyl, could you compare a CD on MBL transport to properly ripped flac on HDX -- both through nDAC?

I wonder if the currently best Naim digital transport can outperform the MBL reference player.

I have auditioned MBL 1622/1611 F combo several times and I have greatly enjoyed its soft, analogue and spacious presentation. On the other hand this 60 K$ monster does not do much over the 18 K$ Linn KDS on Red Books I'm really surprised you didn't like KDS. Did you try it with the latest Dynamik PS?

Posted on: 12 April 2011 by totemphile

Originally Posted by AllenB:

It's Allen, not Adam

Very true, my sincere apologies Mr. B! I must have been absent minded there...

Thanks

Posted on: 12 April 2011 by aysil

Allen,

Thank you infinitely for the detailed explanations of your circumstances when you were making the comparisons. It is important to know what your assumptions were, what you carefully compared, what you paid less attention to, and what you did not compare at all, in order not to miss each other's points. It turns out that we have not compared the same things at all. I wish you had not declared that we had reached contrary results without reading carefully my circumstances. The same applies to me!

You have a NAS based system. When you were comparing HDX and UServe (both as UPnP server and digout), they were playing the same files from your NAS, the same save location, and you did not hear any major differences. This coincides exactly with my observation. I did NOT find the major differences when I changed the server. Whichever server (UServe, HDX, or Asset) I used, it was when I changed the "read location" (UServe HDD, or HDX HDD) that made the big difference! Remember I was using the "local save" versions of both devices, both on the network, and both able to read from each other's HDD through the network.

It may indeed be true, as you point out, that the HDD and signalprocessing/output sections are less isolated from each other in UServe than in HDX and therefore these sections in UServe are badly affecting each other. (Talking about the non-ssd versions) You mention that you suspect the existence of HDD inside my UServe is affecting the performance of its signalprocessing/output sections. It may as well be true. I want to suggest that the reverse may also be true. Namely, that the existence of other components in the vicinity may be affecting the performance of the HDD in UServe. This possibility opens up many variables in both my and your system:

"Notwithstanding any of this, once the digital file has been transferred into the buffer of the music player / renderer all of the storage medium questions become academic provided the file is accurate, especially if the files are stored out-board of that player / renderer."

I want to question this remark of yours. From your words, I understand that you have personally not carefully tested this statement. It is more of an assumption resulting from a line of reasoning based on knowledge on working principles of these devices. You know, I don't want to take such statements for granted and prefer to leave them on the table for thorough testing. The results of your auditionings on the contrary, I am more willing to take for granted, as long as they don't contradict with my observations.

First of all, there are numerous evidence that buffering may not be wiping out completely all variations on the input signal (if not introducing new ones). This is a bit off the topic, let's put it aside for a while and discuss it possibly on another thread.

The claim that "all of the storage medium questions become irrelevant" does not convince me completely and I suggest to question this. There are some people in some internet forums who claim there are sound quality differences between different NAS. This may (or may not) be true. Your NAS, or the HDD of my HDX or UServe are not storage mediums in the sense of fixed CD. There is an active process of "reading" on the location.

Your NAS may have been the constant in your music system, which bound the sound quality comparisons throughout all the history you wrote about. Why not test it once as a variable?

All this brings us to my question on the topic line of this thread. (This was only a question) If for example a NAS is a variable (a component, selection of which varies the sound quality of a system), why not call it a source component?

"Incidentally, you must try plugging the Serve into the same power source as the system, Naim have a bespoke filter on the SMPS, so it won't necessarily kill the rest of the system. OTOH,"

I did try different mains outlets for plugging the UServe, it did not change the result of the comparison.

"Also, as others have suggested, you may need to check the grounding switch and play with the various combinations on all units that have one."

This would maybe effect the overall quality of the system but not the result of the comparison, because UServe does not have a ground switch.

Posted on: 12 April 2011 by aysil

Allen, I did not miss your point, that an accurate rip is an accurate rip. In fact, I accepted it just like that upon your statement and forgot about the possibility that UServe and HDX may have been ripping differently.

I understand your reason for using UServe SSD version and a NAS and I believe UServe is doing the job very well for files saved out-board. This was exactly my experience, too. I am only saying that UServe was inferior in my system for files saved on-board.

Posted on: 12 April 2011 by lhau

Aysil, I just want to reiterate that reading a harddisk is not a factor. The harddisks themselves are designed and do read reliably in a computer only environment. If not, you would have seen Goldman Sachs and all the banks computers use only audio grade circuit, Psu shielding, vibration isolation, fraim on their computers because missing a bit can mean losing a million 552 preamps for them, but only some slight drop in sq for you. I can assure you they don't do that on their computers, it is because harddisk reads accurately is not a theory, it is a fact that is tested billions of them every second on the earth (until the harddisk dies that is). If the reading affects sq, it is more probable the result of the side products of the reading environment (emissions, psu noise transmitted etc) affecting the audio chain rather then the reading itself. Of course if you place the harddisk inside a audio chassis, the harddisk itself being a noisy computer product can directly affect the audio components inside it and it's possible a seagate may sound better than a western digital due to difference emissions etc. If they are housed separately, this direct influence is normally lessen exponentially as they are further apart. Anyways, I just want to say I am not doubting your findings, I am just thinking if you can actually do something about it (like getting the nas and switch as far away as possible, use a good fast switch, use decent cables, separate the music network from your day to day router etc). All of those things would probably cost you less than £300 to set right. Anyways, this is the end of my ranting. I am of course highly interested in your findings as the fable 202 and ndx is definitely in my scope for my ultimate audio system upgrade. Good luck and enjoy the music. After all that is the end result which we are after and I have found that unless you throw some 192kps badly coded files to it, all naim sound beautiful, and even with those mp3s, it always give you the best beats and hearts of the music and always engaging.

Posted on: 12 April 2011 by aysil

Originally Posted by lhau:

emissions, psu noise transmitted etc...

Yes, I think we have been saying the same thing from the beginning. It's obvious that in digital audio, reading the bits correctly is not enough for sound quality, unlike Goldman Sachs banking operations.

Can you please explain why these things matter:

- having a good fast switch

- getting the nas and switch as far as possible

- using decent cables (what cables do you mean?)

- separating the music network from the day to day router

Thanks,

Posted on: 12 April 2011 by lhau

1) as far away as possible to avoid transmitting noise to audio chain. 2) good fast switch to send data quickly and reliably, this will eliminate drop out and resending of data packets, which means lower workload for your ndx to check and receive resented data and always get it on time. 3) network cable should meet gigabit spec, for reason of #3 above. 4) dedicated network for 2 purposes. Firstly, you are essentially connecting each device via network wires, minimize the number of devices to only the nas and server will minimize interference transmission via the network. Secondly, if the network is not dedicated, it is sharing it's bandwidth with other things on the network, again in the interest of #2 above Finally, using the above will eliminate many variables so you can concentrate on optimizing the audio chain.

Posted on: 13 April 2011 by AMA

Originally Posted by aysil:

It's obvious that in digital audio, reading the bits correctly is not enough for sound quality, unlike Goldman Sachs banking operations.

Asyl,

Once the bit is safely delivered to the buffer of re-clocking streamer/DAC it will always produce the same sonic signature, no matter of bit origin (providing the power for output gain stage does not change in time).

Reading the bits correctly from FLAC is also NOT an issue.

The actual challenge of network audio streaming is to transmit the bits from NAS to the streamer/DAC memory buffer. It's quite a long chain: transcoding the bits in uPnP, encoding them into TCP packages, sending the packs over ethernet/Wi-Fi, receiving the packs with streamer's ethernet receiver, decoding the packs, storing the bits into a memory buffer for further re-clocking.

The drivers of ethernet generators and receiver provide multiple check ups to secure the packs are transmitted bit-perfectly.That's it -- since that moment the sonic signature will be pre-defined.

Theoretically the ethernet transmission chain can be flawless as the existing throughput standards exceeds the audio bitrates by a big margin (even for hi-res).

Now let me repeat and be more specific on my claim: if two uPnP servers stream data from the same NAS to the same Client streamer and the sound differs this means that one or both uPnP servers are FAULTY (I mean they FLIP the bits occasionally).