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Post by MartinT on Apr 18, 2020 16:27:20 GMT
One of the more tiresome pieces of disinformation in digital audio replay is that cables and noise cannot possibly affect sound quality as it's just ones and zeros and therefore, if the data is preserved, there can be no variations in replay. Not only does a simple listening test instantly dispel this myth, but a straightforward thought experiment should remind you that all digital signals are represented and carried as analogue waveforms along cables and circuits. There is no such thing as a digital signal electrically, it's always carried as an analogue waveform representing the digital data. Therefore, many things can disturb this analogue representation until the moment it is converted to an analogue signal in the Digital to Analogue Converter (DAC). I have read many explanations of what can happen to the digital signal to affect the resulting sound quality, but this white paper, Understanding how perturbations on digital signals can affect sound quality without changing bits, and how these issues are addressed by the UpTone EtherREGEN, is probably the best explanation I have yet come across. It may be vendor biased towards their product, but the explanatory sections are very enlightening, concise and well explained. cdn.shopify.com/s/files/1/0660/6121/files/UpTone-J.Swenson_EtherREGEN_white_paper.pdf?v=1583429386Let the discussions begin. |
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Post by MartinT on Apr 18, 2020 16:45:22 GMT
If you really don't want to read the full article (I do encourage it), the management summary might be:
1) clock quality preservation (whether by reclocking or other means) is vital
2) noise on the ground plane is critical (this is where grounding boxes help)
3) every component along the digital chain, including cables, has an effect
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Post by Clive on Apr 18, 2020 17:04:16 GMT
If you really don't want to read the full article (I do encourage it), the management summary might be: 1) clock quality preservation (whether by reclocking or other means) is vital 2) noise on the ground plane is critical (this is where grounding boxes help) 3) every component along the digital chain, including cables, has an effect There are very frustrating bunch of deniers around...I mean the bits-are-bits brigade. I don’t deny that it would great if digital audio were like programming (sorry coding), but it’s not. I recently interviewed Norbert Lindemann and in essence it was those three points he focused on. His way of dealing with ground planes is to put as much into one box as possible and thereby having control over the configuration. He deals with cables in much the same way and interestingly he’s dropped USB for audio use as he’s frustrated with the variance in sound between cables. I say “interestingly” as Norbert is a very experienced digital designer as opposed to some of the forum protagonists we see. Norbert’s way is not the only or necessarily perfect approach but it’s the one he settled on with all his experience. |
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Post by petea on Apr 18, 2020 17:35:28 GMT
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Post by julesd68 on Apr 18, 2020 17:53:47 GMT
The dude from Audio Science Review measured and listened to the unit and came to the conclusion -
< Measurements conclusively demonstrate that EtherRegen did not change jitter, noise or distortion of the DAC. It further had no impact on its clock speed, or output voltage ... and there is no audible difference either. >
I am not saying he is wrong or right (and haven't heard this unit) but why can his opinion be immediately discounted?
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Post by Clive on Apr 18, 2020 17:56:27 GMT
Amir has a very strong agenda and his own consulting company. He used to manage the HDCD team at Microsoft after they were acquired. He’s a very narrow viewpoint.
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Post by MartinT on Apr 18, 2020 17:57:24 GMT
Because he didn't measure what we can hear.
He seems to think that measurement defines exactly what we can hear and anything else is in our imaginations. Yes, I do dismiss it as I know better.
Not an ego statement.
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Post by Deleted on Apr 18, 2020 17:58:37 GMT
Just think all those anally retentive folks hanging around in south west England and poo poo 0 volt centralising issues must weight heavily on AP users 
Everyone favourite AP extoller of year award had some words of wisdom a few years back
Amirm from asr
"THD+N is perceptually blind. That is, its value does not correlate with how we hear (i.e. ignores masking thresholds). For that reason I don't use THD analysis in my AP. Just do a spectrum analysis with the original signal still there and look at the distortions spurs."
Mr P Miller once proclaimed at a particular show he could absolutely describe the sound of a piece of digital replay equipment by the sidebands alone  whilst being 100% sober.
Mind you the 'great' Keith Howard and his speaker measurements using wobbly microphone stands and taped up mic's with the saying 'It'll do they are only idiots anyway' from a tale not so long ago
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Post by julesd68 on Apr 18, 2020 18:19:30 GMT
Because he didn't measure what we can hear. He seems to think that measurement defines exactly what we can hear and anything else is in our imaginations. Yes, I do dismiss it as I know better. Not an ego statement. So what conclusion have you come to about this EtherRen unit Martin? The problem is that even if we agree that digital is about more than ones and zeros, and ignoring measurements, people can and do regularly come to totally opposite opinions on the effectiveness of such a unit. There is no way to prove that one opinion is more valid than the other and so it all becomes a bit futile. Just like mains cable debates etc etc |
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Post by MikeMusic on Apr 18, 2020 18:30:04 GMT
The world is far more complicated than ones and zeroes. The more we find out the less we find we know - you can use that one if you like |
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Post by John on Apr 18, 2020 18:32:05 GMT
I think Tony C can prove with the equipment he got that there is something measurable going on in all of this.
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Post by MartinT on Apr 18, 2020 18:35:41 GMT
So what conclusion have you come to about this EtherRen unit Martin? I haven't come to any conclusion as I don't have it yet. However, I have learned much from the Mutec reclocker and every link in my digital chain. |
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Post by julesd68 on Apr 18, 2020 18:51:14 GMT
I think Tony C can prove with the equipment he got that there is something measurable going on in all of this. So you feel measurements are valid depending on who is taking them and what gear they use? I don't think there is any 'universal truth' to this issue as a whole - it needs to be taken on a product by product basis as to whether said product has achieved its design goal. |
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Post by John on Apr 18, 2020 18:57:04 GMT
I am not sure what I think Jules
I just know what I hear and that good enough for me I am not on a crusade to convert others who have a different experience. I just wish they would give me the same respect.
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Post by MartinT on Apr 18, 2020 18:57:20 GMT
I think Tony C can prove with the equipment he got that there is something measurable going on in all of this. His work on ground planes proved conclusively to me that noise and grounding boxes correlate with what we were seeing. |
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Post by MartinT on Apr 18, 2020 20:02:35 GMT
I am not on a crusade to convert others who have a different experience Different experience - agreed. It's pointless to argue. No experience - I cannot take the opinions of people who haven't tried it for themselves seriously. The white paper in my o/p is an excellent read and states clearly the kinds of jitter, phase noise and PSU leakage current that matter in a digital circuit. Argue those points, not opinions. |
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Post by MartinT on Apr 18, 2020 20:13:18 GMT
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Post by Deleted on Apr 18, 2020 21:33:28 GMT
The issue here is not who is conducting the measurements or what with etc but defining a meaningful standard that actually relates to a given industry reference standard that really delivers a proper premise.
As far as measuring jitter before and after any device under test and you do not require an audio analyzer to do this accurately or in a repeatable provable manner.
The same for 'shot' noise and ground plane leakage also poorly designed ground plane veers and impedance mismatching , poor circuit board layouts all of these can be measured and modelled with a respectable oscilliscope and are done so every day in pretty much all high speed digital designes
Power supply line ripple and ac incoming harmonics and common mode noise. Switching frequencies on/off times etc all contribute to jitter even after EMC compliance has been achieved. It is merely a safety average to help reduce the amount of conducted and raditated emissions.
Not the be all and end all for ultimate rfi/emi removal.
If you talk to rf engineers and high speed digital engineers these are ever day concerns that are addressed in pretty much all designs
We can even model ciruit pathways with virtual probing techniques and perform very detailed and accurate transmission line measurements on bare circuit boards and populated ones all of these abilities have been available for quite done time
Audio doesn't seem to engage to much in these practices unless it attracts a large price tag
Difficult to find a truly neutral playing field in which to have a quality discussion
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Post by MartinT on Apr 18, 2020 21:51:06 GMT
I believe you're right in that it's not necessarily that we cannot make the measurements required, but that many audio engineers do the minimum necessary to get the circuit working without making the effort to fully debug and run it optimally. In many cases, it would appear that they simply don't know how to.
This is pretty much what John Swenson is saying.
What we, the audiophiles, are left with is selecting components very carefully, combining and connecting them even more carefully, and then paying excruciating amounts of time and attention to power, noise, decoupling, cables, modifications and other environmental factors to get the very best performance from it all.
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Post by Deleted on Apr 19, 2020 10:33:15 GMT
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whilst being 100% sober.
