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Sound quality differences between NAS units
18-08-2016, 18:10
Post: #1
Sound quality differences between NAS units
I recently acquired a Linn Akurate DS/2 and have two NAS units connected to the same network switch: a Synology DS214 and a WD MyBook, both running Minimserver. The libraries are identical. Oddly, sound quality from the MyBook is clearly superior to the Synology. Vocals are much more open and "there" in the room. I would have expected if either NAS would sound better, it would be the Synology. But in comparison, it has a slightly shut-in sound. Minim options are the same for both units. Is there something in the configuration of the Synology that I might tweak to change this? Has anyone else noticed clear differences between NAS units when using Minim?

Adam.
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18-08-2016, 21:46
Post: #2
RE: Sound quality differences between NAS units
I have noticed a significant difference between a "standard" NAS and a specialist NAS like Melco. Some notice differences between having disks in raid 0 and raid 1 and others between the disk manufacturer and type (Hdd or SSD). Please do not ask me to explain why or how but differences do exist.

Melco N1ZH/2 (updated to EX) MinimServer2, Chord M Scaler, DAVE, SPM1200MKII, Wilson Benesch Vectors
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19-08-2016, 07:18 (This post was last modified: 19-08-2016 07:18 by lyapounov.)
Post: #3
RE: Sound quality differences between NAS units
Your WD Mybook is connected to what ? NAS is ethernet, but Mybook is USB ???

I have noticed an improvment on synology the day I have added streaming conversion flac to wav24 (on an akurate as well). The only reason I can imagine is that it puts less stress on the Linn, as the conversion flac to wav is done on the server and not on the renderer.
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19-08-2016, 07:24 (This post was last modified: 19-08-2016 07:25 by Mike48.)
Post: #4
RE: Sound quality differences between NAS units
Though I have only one NAS (a Synology, as it happens), I don't doubt the difference. I have heard this before and seen reviews as well. I think Simon posted comments along these lines, too. From an engineering point of view, I find it interesting and disturbing.

Back to the original poster's question, I wonder
  1. What, if anything, might be done in software to minimize this difference?
  2. How much does this depend on the renderer and DAC?
  3. Is the effect more pronounced with an Ethernet or a Wifi connection, or does it make no difference?

Mike

Mike
Portland, Oregon, USA
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19-08-2016, 10:01 (This post was last modified: 19-08-2016 11:01 by DavidHB.)
Post: #5
RE: Sound quality differences between NAS units
This issue does surface from time to time; I seem to recall an attempt on the Lejonklou forum a while back to rank NASs for sound quality. Whatever you think of that, there seem to be enough independent observations of differences between NASs to suggest that the observers were not deceiving themselves. At the same time, it is reasonable to suppose that the laws of physics have not been suspended for their or our benefit. The observed behaviour has to have a cause, and that cause (whatever it is) has to be able to travel through the network and affect the sound quality of the output of the player.

I can think of 3 candidates for consideration. The first is that the bits and bytes of the digital stream are somehow changed. Personally, I think that the workings of TCP/IP (chopping up the stream into packets at the sending end, routing those packets through the network, and then reassembling the stream, using error checking, at the receiving end) make data corruption a fairly unlikely possibility. The next possibility is that different devices introduce different, but always minuscule, degrees of timing error ('jitter') as they handle the data. As most quality players have highly accurate clocks to which they lock the data stream at their end, it seems to me that the concept of a NAS (or any other network component) introducing jitter which the players cannot handle is somewhat implausible. But, with my limited knowledge of the subject, I could be wrong about that.

This leaves the third candidate - noise. Noise is all-pervasive in electrical and electronic systems, and the digital domain (which is typically only interested to know whether a transmitted value is a 0 or a 1, so off or on) is tolerant of high levels of noise. If (or rather when) that noise percolates into the analogue domain, the story is very different; one of the markers of top quality systems is a high (these days, very high) signal to noise ratio, and a correspondingly low noise floor. I believe that, as time goes on and technology develops, the elimination (or, more likely, the control) of noise at all stages in the reproduction chain, both digital and analogue, will become even more important than it has been up to now.

Coming back to the difference between NASs, if noise is the issue here, where does it come from? Well lots of places probably, but there is a strong body of opinion that points the finger at power supplies. Over on the Linn forum, for example, you will find plenty of references to experiments, both in conditioning mains power (a favourite topic in the US and Canada, it seems) and in replacing or modifying the power bricks and wall-warts that come with most of the devices we buy these days. Would power supplies be the issue in the present case? I don't know, but a combination of improving the power supplies and network noise isolation would be the first possible remedy I would try.

The point here, of course, is that it is probably misleading to think of a NAS in isolation as having a sound, good or bad. What it (or, more probably, its power supply and network interface(s)) does is affect sound quality in particular installations. It is not surprising that, in a given context, different NASs will behave differently. Whether they exhibit the same differences in a different context is, of course, another question.

David
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19-08-2016, 12:40
Post: #6
RE: Sound quality differences between NAS units
I would certainly concur with David's analysis regarding power supplies considering the extreme lengths high end audio manufacturers go to when designing their power supplies. Unfortunately, a NAS (with some exceptions) is still regarded as a computer not audio device where wall wart supplies are quite adequate. Add to this the fact that the human ear is an extremely sensitive organ and can detect minuscule variations in timing and phase, just the factors governing the sound stage experience. I do think that it is a bit flippant to assume that the re-clocking that a renderer performs will eliminate all digitally borne errors so my own view is that the NAS must be regarded as an audio component, and as an audio component, there will be sonic differences between devices.

Melco N1ZH/2 (updated to EX) MinimServer2, Chord M Scaler, DAVE, SPM1200MKII, Wilson Benesch Vectors
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19-08-2016, 16:26
Post: #7
RE: Sound quality differences between NAS units
Hi,

the music which is digitally stored on a NAS is

1) read from the storage medium,
2) sent over the network,
3) received by the renderer,
4) D/A-converted,
5) amplified,
6) converted in pressure variations of the air,
7) transmitted over the air,
8) received by the human ear, and
9) processed by the human brain.

This is a rough categorization and these steps may be split in many more detailed intermediate steps.

Steps 1) to 3) are digital and I think that it is important for anybody with a basic technical understanding to emphasize that modifications to parts involved with these steps _do not_ affect the quality of sound. Specfically, buying a different NAS, using an SSD instead of a HDD, an expensive power supply for the NAS, expensive network cables, etc. _will not_ improve the quality of sound in your system. No way different such components will provide a 'warmer sound', a 'more open voice' or other sound improvements.

Clearly, devices involved with steps 4) to 6) (renderers, amplifiers, speakers) do affect the quality of sound.

And no doubt, a great influence on the perceived sound quality is the device involved with steps 8) and 9) - the listening individual itself.
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19-08-2016, 17:49 (This post was last modified: 19-08-2016 18:21 by Mike48.)
Post: #8
RE: Sound quality differences between NAS units
To summarize what I understand people to have said:

If a NAS introduces noise on the Ethernet line, and the noise is passed through by the (digital) renderer to the DAC, and the DAC doesn't filter it out, either, we hear some degradation of the sound? Is that the prevailing hypothesis to explain this observation? How does that relate to the inevitable other devices connected to the network? (If I remember a review of the Melco correctly, they advise connecting their NAS and the renderer together and to nothing else, but to me that is not a useful form of networked audio.)

If noise on Ethernet is a problem, would using WiFi eliminate the problem, at least in theory?

I'd like to understand what is being proposed here. Given the excellent sound quality I've heard extracted from music on a Synology NAS, I am dubious how big an issue this could be. However, audiophiles are interested in many changes that I might find to be second-order or third-order effects -- smaller than moving one's listening seat by 15 cm, for example. I have to agree with Win Xi that the biggest variable, at least in my case, is often the ear-brain system.

Mike
Portland, Oregon, USA
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19-08-2016, 17:52
Post: #9
RE: Sound quality differences between NAS units
Thanks all for the comments, particularly David's which I think is one of the most thoughtful commentaries on this topic I've ever read.

I did not come at this with the objective of doing an A/B test. I'd been running the Synology for about a year, having previously managed to get Minimserver running on the MyBook with Simon's help. The MyBook got packed away, though I've never been that thrilled by the sound from the Synology. Recently, I decided to update the library copy on the MyBook and happened to be running the MyBook as my server for a few days, and I started to notice I was rather enjoying the system. But then, deciding I didn't really need two NAS units all the time, I shut it down again and reverted to the Synology, and then the difference in SQ jumped out at me. We're not talking an ultra subtle difference, it's obvious. Yet the MyBook is a lower-spec NAS. But then how to explain it? The bits must still be getting to the streamer, and surely the Akurate should be re-clocking in some way. So I do wonder about power-supply noise, and that in turn raises the interesting idea that there may be an interaction element with the local environment, which could explain why the same NAS might sound amazing in another location. I may investigate further, but it sounds like playing about with configuration options with the Synology unit itself is unlikely to be a useful place to start.
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19-08-2016, 18:55
Post: #10
RE: Sound quality differences between NAS units
(19-08-2016 16:26)winxi Wrote:  Steps 1) to 3) are digital and I think that it is important for anybody with a basic technical understanding to emphasize that modifications to parts involved with these steps _do not_ affect the quality of sound. Specfically, buying a different NAS, using an SSD instead of a HDD, an expensive power supply for the NAS, expensive network cables, etc. _will not_ improve the quality of sound in your system. No way different such components will provide a 'warmer sound', a 'more open voice' or other sound improvements.

I am sorry but I have to disagree. Listening tests have proven otherwise to me. As a retired electronics engineer I am at a loss to explain how or why but I shall stand by what my ears tell me. How the digital domain is handled DOES affect sound quality! I suspect that in the end we shall have to beg to differ on our stances.

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