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: 09 April 2011 by aysil

CONCLUSION 3:


Audio manufacturers do not yet address the issue of sound differences of different computer sources. They don’t produce computers themselves. (Naim is almost the only exception, producing hard-disk players, and I think this was a very clever move. This was one reason I got interested in computer audio.)


For a long time, I did not take computer audio seriously; I thought the general-purpose computer was too noisy an environment to serve as a quality source for a high-end system. I am now reconsidering my position on this. As I am using NDX more and more, and listening to the downloads in my computer (mostly from Naim-store), I think the computer is a serious source component – although not the best source in my system yet. I still believe however, that the ideal solution would be music-optimized computers designed-and-manufactured by audio companies! Naim’s experience in this field will prove to be significant in this future.

Posted on: 09 April 2011 by Mr Underhill

Hi Aysil,

 

Interesting write up.

 

I haven't had the HDX at home, but do use an NS01. I preferred this to the UnitiServe, but would never describe the US as nervous and rough.

 

In fact through my system, which like yours does not use Naim amps for my main speakers - I use EAR, I would describe the US as warmer.

 

I felt the NS01 resolved more information and presented a better image.

 

I could imagine many people preferring the US.

 

Out of interest did you play with the ground settings? I have found these make a big difference?

 

M

Posted on: 10 April 2011 by Patu
Thanks for an interesting write up. There was one part of the text which bothers me though.
 
Originally Posted by aysil:

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.

 

A source component is the only correct term for NDX. It includes both parts of digital signal chain - transport and D/A-converter. It's as much a source than any CDP out there. Computer plays no role in audio signal here, it just streams the raw data to the NDX which processes it from the scratch. PC or MAC with NDX is only for controlling what music you stream to the NDX. Saying that different ethernet cables would make any difference is ridiculous. Even with wireless streaming you should achieve exactly the same results. 

 

I just bought the nDac and received it on friday. Compared to my SuperNait's integrated DAC this thing is purely awesome. Still I have the problem of how to transfer the data from PC to the nDac. I currently use Audio GD Digital Interface which is the best USB to S/PDIF converter I've heard so far. It does great job but it still bothers me that there's probably better ways of doing the transportation. NDX eliminates this problem as it does everything inside one box. You only have to stream the raw data from PC or MAC and NDX does the job. I will most probably in some point audition NDX as it'd be a perfect solution for me, eliminating the need for separate transport like Audio GD. 

 

Originally I didn't believe in differences between different transports. Now when I've auditioned many of them, I know that there's a clear difference between them. I have concentrated to USB to S/PDIF converters as I use a PC for my main source. 

 

(IMHO)

Posted on: 10 April 2011 by likesmusic

If a UnitiServe and an HDX sound different via UPnP to an NDX then at least one of them is faulty. (imo).

Posted on: 10 April 2011 by aysil

Mr Underhill,

NS01 and HDX are similar designs and I can assume they sound similar. It is comforting for me to know that you have also heard differences between NS01 and UServe and made your preference. I accept some people could prefer UServe in their system. It is a matter of personal taste and system tuning. We should also not be distracted by the terms I used for describing the sound of the devices. We may be using the same terms for describing different phenomena and misunderstanding each other. My main point is that there ARE sonic differences between computer sources; and the recognition of this fact just opens up a vast area of VARIATION and IMPROVEMENT, which may have been a bit overlooked up to now.

Posted on: 10 April 2011 by Patu

If by computer source you mean PC/MAC connected to USB to S/PDIF converter, then I agree with you. If you're trying to say that it matters what kind of ethernet cable or from which storage device you stream the data to the NDX, then I must strongly disagree.

Posted on: 10 April 2011 by David Scott

"My friend accompanying me during the auditioning did not even believe we were playing the same track!"

 

He may not be a very reliable witness then.

Posted on: 10 April 2011 by Tog
Fascinating post







Logically UPnP should shift the onus for SQ to the renderer as the source. However, I don't think the HDX and the Serve are the same kind of machine at all and find it difficult to believe why an SSD Serve would sound worse.







IME flac via UPnP does sound better than wav/aiff via dig out to a Uniti by quite a distance but I am sure that has more to do with Naim's renderer than the server which is just providing the flac file over a network. There should't be much too choose between HDX/Serve and if anything an SSD Serve should sound better - it is certainly a simpler more eloquent solution than the HDX.







Tog
Posted on: 10 April 2011 by lhau
I have not yet reach that high revealing end yet, but I would like to point out a seemingly flaw in logic in describing the ndx is not a source but a intermediary piece. I would say that if your g applies, then cd players are not a "source" too. It is reading a cd, and the machine that master the cd is the "source", so to speak. I say this because the ndx is trying to read a sound file, much like a cd player/transport is trying to do.
Posted on: 10 April 2011 by aysil

Patu,

"NDX includes both parts of digital signal chain - transport and D/A-converter"
IMHO, this is not true; NDX does not include a transport. The digital data is streamed from a computer, which is THE source component.


"Computer plays no role in audio signal here, it just streams the raw data to the NDX which processes it from the scratch."
I am not sure if this is the full technical truth about streaming. This is just a general statement which describes the WORKING PRINCIPLE of streaming. There may be innumerable technical details of reading the data from the hard drives, packaging them, and sending them etc etc that influence the sound quality already in the computer itself. Please let's not just rule out such factors with our pre-assumptions. I may be wrong but it took me literally weeks and many hours of careful listening to suggest this possibility. So  far, I have only compared HDX and UServe as examples of two different computer sources I will bring some macmini from my office and compare it with my laptop. I will continue reporting to you my experiences.


"Saying that different ethernet cables would make any difference is ridiculous"
Please let's not call each other's suggestions "ridiculous" just because it contradicts our previous knowledge. Actually, some weeks ago, there was a member who posted his experience of improving the sound by changing his CAT cable. He was pretty much mocked at, which is not the purpose of this forum.


"If you're trying to say that it matters ... from which storage device you stream the data to the NDX, then I must strongly disagree."
Dear Patu, you are disagreeing without having auditioned the NDX! None of us in this forum have infinite technical knowledge in this field to enforce assumptions. I invite you to my home to listen to NDX and try it yourself. I also had assumptions, which proved to be wrong through experience.

Posted on: 10 April 2011 by Tog
Not convinced - by the logic of your argument it is the CD itself which is the source with the CD player the renderer which would be fundamentally correct. However, most here would see the renderer CD or Uniti/Qute/NDX/Squeezebox etc as the effective source component.







Tog
Posted on: 10 April 2011 by aysil

Allen B,

I think you missed some of my points, because I was not able to express them clearly.

I am definetely not trying to "assasinate" UServe. I am sorry if I caused such a misunderstanding. On the contrary, I acknowledge it is one of the best source components out there. I just detected clearly noticable differences to HDX, and HDX was MY preference in MY system. And comparing HDX to another source, I may have prefered that other source. I totally respect if other people have other preferences. However, I do want to challange the quite common assumption, that differences are not to be expected among computer sources especially if the data is being streamed. This is the main topic I want to discuss.

I have used 500 series amplifiers im my system for a long time and I still love them. At some stage, I preferred to switch to tube amplifiers, I think this decision of mine should also be respected. If somebody wants to stay in the solid-state domain, I always recommend the Naim amplifiers. I really see no reason to look elsewhere. I am totally convinced that Naim amplifiers, especially the 500 series, have wonderful resolution and would be able to reveal the sonic differences I have reported on my post. I am also sure that you would be able to hear the differences if you made such an auditioning.

"The HDX and the Serve are essentially the same 'source computer', using the same operating system, and the same bespoke ripping engine."
I am not going to agree with you on this. If we say having the same operating system and ripping engine would make them the same source computer, we would be ignoring the influence of many known and unknown factors influencing the sound. I am absolutely not assuming that a source component should be better because of its higher price; I am writing just the results of my auditioning. I am sorry but I just don't want to bound and limit myself with a pre-assumption that UPnP servers should sound the same - especially if this assumption is contradicting my real experience.

Posted on: 10 April 2011 by aysil

BTW, because of previous warnings on this forum about the possibility of UServe's ps contaminating the mains, I connected UServe to a separate and isolated power outlet, and it was always on and playing even when it was not the auditioned source.

Posted on: 10 April 2011 by Patu
Originally Posted by aysil:

Patu,

"NDX includes both parts of digital signal chain - transport and D/A-converter"
IMHO, this is not true; NDX does not include a transport. The digital data is streamed from a computer, which is THE source component.


"Computer plays no role in audio signal here, it just streams the raw data to the NDX which processes it from the scratch."
I am not sure if this is the full technical truth about streaming. This is just a general statement which describes the WORKING PRINCIPLE of streaming. There may be innumerable technical details of reading the data from the hard drives, packaging them, and sending them etc etc that influence the sound quality already in the computer itself. Please let's not just rule out such factors with our pre-assumptions. I may be wrong but it took me literally weeks and many hours of careful listening to suggest this possibility. So  far, I have only compared HDX and UServe as examples of two different computer sources I will bring some macmini from my office and compare it with my laptop. I will continue reporting to you my experiences.


"Saying that different ethernet cables would make any difference is ridiculous"
Please let's not call each other's suggestions "ridiculous" just because it contradicts our previous knowledge. Actually, some weeks ago, there was a member who posted his experience of improving the sound by changing his CAT cable. He was pretty much mocked at, which is not the purpose of this forum.


"If you're trying to say that it matters ... from which storage device you stream the data to the NDX, then I must strongly disagree."
Dear Patu, you are disagreeing without having auditioned the NDX! None of us in this forum have infinite technical knowledge in this field to enforce assumptions. I invite you to my home to listen to NDX and try it yourself. I also had assumptions, which proved to be wrong through experience.

As Tog already wrote, by your logic, with CDP the CD would be source and the CDP only a "renderer". Because with NDX, PC/MAC is comparable to a CD disc. It's just a storage device for the data. Of course it matters how you have ripped your music and in which format it is etc etc. but in the end PC/MAC is only a storage device in NDX based setup. 

 

Sorry for calling your opinion ridiculous but when you just stream the raw data, there won't be any difference between the ethernet cables. Wireless streaming is different story though, you might experience some interference in the signal because it travels through air but in the end the data is processed only after it gets to the NDX. 

 

I haven't heard the NDX yet but I have auditioned Linn Majik DS which functions just like the NDX. We didn't compare different ethernet-cables but I know few people who own DS-based Linn-setups and I have never heard reports of differenceis between ethernet-cables. It just doesn't make any sense.

 

Thanks for the invitation. I'd love to audition NDX but I assume you live in GB. I'm from Helsinki Finland so it'd be quite a trip for an NDX audition. I'm eagerly waiting when our importer gets the first units. 

Posted on: 10 April 2011 by Tog
Lovely country Finland.



Agreed, HDX/NDX/Uniti are renderers so any differences between them are likely to be created by either their software or hardware implementations. Assuming that is that you are using the same separate UPnP server and the same ripped file any differences are not created by the network stream.



Tog
Posted on: 10 April 2011 by aysil

could somebody tell me if the USP cable used to connect to the computer play a role in sound quality when using a DAC with USP input?

Posted on: 10 April 2011 by aysil

"I would say that if your g applies, then cd players are not a "source" too. It is reading a cd, and the machine that master the cd is the "source", so to speak."

"by your logic, with CDP the CD would be source and the CDP only a 'renderer'."

 

These remarks are total misinterpretations of what I was saying. I will try to explain my line of thought one more time. I hope it helps:

 

The actual source is of course the recorded live music event itself. Of course, as consumers, we have no influence on the recording process. The source component in our home is the first active component in our audio system. The cd-disk is not active, it does not do any reading itself; and once it is pressed we cannot change or improve it. We can maybe clean it or put it in a demagnetizer, but these just improve the precision of the reader of the disk, which is the cd-transport, or the cd-player.

 

The computer (pc/mac, harddisk-player or whatever) is an active component in our system! The data on the hard disk is read in the computer. Data reading of an hard disk is a process full of errors. Further, this data is processed in order to be sent in the UPnP stream. This process is also prone to many and many errors.

 

WHERE DOES THIS NAIVE ASSUMPTION THAT COMPUTER PROCESSES ARE ERROR-FREE COME FROM?  I really don't understand. It is as if there is some kind of idealization or even divinization of the computer going on here. The reality is just the contrary. Computer is a very "earthly" entity! That's why computer scientists are struggling hard to find ways of error correction. Why do disk drives make use of error correction codes? Why was codes like Reed-Solomon Error Correction was developed and integrated into computer processes?

 

The degree of precision of the data reading and processing in the computer is an important factor in the sound quality of the system. The factors in the computer which influence the sound are active processes. That's why I call the computer as the "source component" and data clients like NDX as "intermediary components" of the music system.

 

The computer is capable of many tasks. Audio is fundamentally different from all these other tasks. In all computer documents and even in high resolution video, we are dealing with representations. We perceive of  the video image as a representation of the imagined. In audio, however, it is another kind of perception; we are seeking an illusion, the illusion that the music is taking place in our room! The human ear (of course the human brain) is extremely sensitive to any change in the sonic data in the process of creating this illusion. Any small change in the data presented to this highly elaborate system alters the perception of the illusion.

 

I hope I've made it clearer now.

Posted on: 10 April 2011 by lhau
Aysil, Firstly I want to say while I do not take a position and is open that different server/ripper may make a difference, I have to disagree with your logic. Contrary to what you day, computer is actually the most sensitive to non bit perfect stuff. A shift of a bit in a program will cause it to crash, a bit shift in a word file will cause it from changing the content or structure or even unreadable, a bit shift in the wrong part of the disk can cause a large part of a disk to be totally unreadable. That is why computers are designed to be bit perfect, and when you copy your file from disk to disk, network to network over a dozen of times and then email it through an unknown number of routers and servers, it is still the same when your friend open it in the other end of the world. I think it is not people familiar with computers that brings the crazy idea about computer being bit perfect, on the contrary, it is the audio side bringing the wrong analogue to the computer data. You can actually test this in a local network, if you ping another computer on your network, you should see 100% of data succeeded and with crc check correct, Zero bad data packets and zero resend. If not, something is wrong with your networking or one of your computer. With my old version Mac able to copy the entire CD worth of music in one minute, and able to transcode a several minute track in a few second, there is nothing from the computer side that drags your "source" ino filling it's buffer 100% with exact data. I still think you bring too much idea from audio. If a ndx is not a source, nothing is. It is the first component in your chain that attempts to do something to the audio data. You have a transport analogies that is not right. Audio doesn't require a cd. If you download a file from naimlabel, copy it to a USB and plug it in the ndx, would you argue that the naimlabel us the source because it is the first active component? Or would you argue the USB chipset is the source? actually your store and forward router maybe the source if you play it upnp? I think if there is a difference between server, it maybe down to the servers transcoding the files differently, or the amount of emission carry o your source via the Ethernet cable etc. To argue that somehow just because the file is audio data the computer lost it's ability to read, send, copy it perfectly like when it normally does reading your office files, program binaries etc is just not the right direction it seems.
Posted on: 10 April 2011 by Patu
Well written lhau.
 
Originally Posted by aysil:

The computer (pc/mac, harddisk-player or whatever) is an active component in our system! The data on the hard disk is read in the computer. Data reading of an hard disk is a process full of errors. Further, this data is processed in order to be sent in the UPnP stream. This process is also prone to many and many errors.

 

 

IMO, computer is active component only if it's used with a separate USB to S/PDIF converter or even worse, with PCI sound card. With the separate converter you have to configure your media player to output bit perfect data (like foobar2000 with WASAPI or ASIO output). With a complete source system like NDX, you don't have to worry about this. NDX truly is the first component in the signal chain which processes the signal in any way. 

 

If data reading of an hard disk is full of errors then shouldn't all the CD-players reading CD's be full of errors too?

 

Posted on: 11 April 2011 by james n
Originally Posted by aysil:

" 

The computer (pc/mac, harddisk-player or whatever) is an active component in our system! The data on the hard disk is read in the computer. Data reading of an hard disk is a process full of errors. Further, this data is processed in order to be sent in the UPnP stream. This process is also prone to many and many errors.

 

WHERE DOES THIS NAIVE ASSUMPTION THAT COMPUTER PROCESSES ARE ERROR-FREE COME FROM?  I really don't understand. It is as if there is some kind of idealization or even divinization of the computer going on here. The reality is just the contrary. Computer is a very "earthly" entity! That's why computer scientists are struggling hard to find ways of error correction. Why do disk drives make use of error correction codes? Why was codes like Reed-Solomon Error Correction was developed and integrated into computer processes?

 

The degree of precision of the data reading and processing in the computer is an important factor in the sound quality of the system. The factors in the computer which influence the sound are active processes. That's why I call the computer as the "source component" and data clients like NDX as "intermediary components" of the music system.

 

The computer is capable of many tasks. Audio is fundamentally different from all these other tasks. In all computer documents and even in high resolution video, we are dealing with representations. We perceive of  the video image as a representation of the imagined. In audio, however, it is another kind of perception; we are seeking an illusion, the illusion that the music is taking place in our room! The human ear (of course the human brain) is extremely sensitive to any change in the sonic data in the process of creating this illusion. Any small change in the data presented to this highly elaborate system alters the perception of the illusion.

 

I hope I've made it clearer now.

Err no - this really is rubbish.

 

Computer processes are error free - that's what computers do. Give it a mathematical task to do and the answer is the same over and over again. Reed Solomon coding is just used to detect and correct errors found on the hard disk - ie minor sector read errors. If the errors are too big then you get a read error, not bad data.

 

Given the same file and the correct UPnP server, the results will be the same everytime (negating any EMI type influences) . With time dependent data such as an S/PDIF signal, the influence of the computer is quite significant but with UPnP via Ethernet this is not an issue.

 

 

James

Posted on: 11 April 2011 by Tog

Source Media =  CD/LP/Digital Stream

Renderer / Source Component / Transport  = Uniti/NDX/HDX

 

As long as your Source Media is OK - any differences will be with your Source Component.

 

NB: There well be minor fluctuations with digital streaming - sun spot activity - gravity wells - the weather or your state of sobriety. Just not enough to worry about unless you love worrying about stuff.

 

If the source components sound different with the same media it would be logical to assume that it is the component and not the media that is the culprit. The Uniti/NDX/HDX are all quite different machines and it would be odd if they behaved or sounded exactly the same. Whether the sound is better or worse is a moot point as it depends what you like, how you are feeling and bizarrely (with me) the time of day.

 

It is worth pointing out that scientifically proving that one thing subjectively sounds slightly worse than the other is rather fraught with problems. If you like the sound of something it is difficult to take "you" as a variable out of the equation without a lot of effort and focus group testing. Politicians rely on focus groups a lot and we know where that gets them.

 

I think there is a degree of delusional psedo-science out there regarding music reproduction. In a world where a global coffee brand uses the strapline "We don't make coffee, we create it!" you need to be very aware of all the BS out there.

 

Another thought occurs to me as well - how lucky or selfish are we to be able to spend time fretting over the slight differences of HiFi kit that costs thousands of spondulicks in a world were most of our brethren have more mundane issues to ponder than their flac files.

 

Now that is worth worrying about....

 

Tog

 

 

 

 

 

 

 

Posted on: 11 April 2011 by aysil

The fact that the computer does a mathematical task correctly does not mean that there are no errors on its hard discs. All this discussion carries us to topics that should be discussed by computer scientists. I am not a computer expert. What I know even with my superficial knowledge is that computers are in a continuous activity of error correction on all levels - in order to keep the errors below the level of file corruption or read error.

 

What I suggested was that this processing power "wasted" in error correction could be ONE OF THE FACTORS influencing the sound. I may be wrong; maybe it is not a factor at all, but my suggestion is not rubbish. If there are computer experts on this forum who could recommend further reading on this topic, I am willing to develop my knowledge. The fact that some computer audio experts report even different media-players sound different with the same bit-perfect data etc imply the existence of many other factors.

 

Actually, it is not so significant for me why the differences occur. The plain and undeniable fact is that different hard-disc players sound different. In my experience, the differences between the hard disk players I compared were more significant than the difference btw the dac section of NDX and nDAC - an issue many are discussing eagerly since the introduction of NDX.

Posted on: 11 April 2011 by aysil

AllenB,

I still got stuck - and very much hurt - by the fact that you declared my write-up as "disingenuous". I try to be polite in my expressions. Maybe that's why you perceived it as such. I want to be as straightforward as possible, but I read in some previous posts that people may react very personally to too straightforward comments.

Maybe my bad English is a problem...

Posted on: 11 April 2011 by james n

The plain and undeniable fact is that different UPnP servers sound different.

 

It's not a fact - it's your opinion. Given the same file, via UPnP, it shouldn't make any difference whether it's come from the HDX or the Serve. I can understand if the UPnP server implementation is wrong or some transcoding is taking place where it shouldn't  then they could be different but in this case If these sound completely different then either Naim have got it wrong somewhere (or you have a faulty unit) or your setup is compromised in someway. Given some of your assumptions above i suspect the latter.

 

Have you set the grounding correctly as mentioned above although this shouldn't affect the NDX Etheret connection due to galvanic isolation ?

 

Is your system very sensitive to the different PSU's used in the HDX / Serve ?

 

 

 

 

 

 

Posted on: 11 April 2011 by Gilles

Hi,

 

I have been working in research in telecommunications (wireless networks) for 15 years and I would like to clarify some points:

 

- In an audio CD there is no inner checksums and therefore there is no way to guarantee that no error have been made when reading it. What DBPoweramp does for example is to calculate one after having read the CD and to compare it either from a database or between different successive readings. If the calculated checksum is the same then the probability that there was an error is low (but can not be completely removed).

- Computers process data for which a sophisticated error correction mechanism exists. Just open your resource monitor in your PC and you'll see that there are many errors which are detected when reading the RAM. Thanks to the error correction mechanism they are detected and fixed.

- On a network there are also many errors on transmitted data: that is why TCP has been designed. It provides a retransmission mechanism which aims to increase the reliability of the exchanged data. Nonetheless even TCP is not totally error free in a stressed network. On the equipments I have been working on, we had to add an additional layer to increase the reliability.

 

As a Linn DS user I have to say that adding a switch to my network instead of using the ADSL modem router and changing my Ethernet cable made a difference. A big one in the first case (bigger than changing my interconnect cables for example). There may be many explanations to that but, even if I have an electronic engineer degree, as I am not specialised in audio signal processing I let the audio specialists to try to find one. But what I know is that timing matters and I guess (it is just a guess) that numerous retransmissions must be an issue (buffering and reclocking should diminish the impact but perhaps not completely).