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Surprise findings on Ethernet cables/cleaners/reclockers

pkane

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This was posted on another forum (in German):

Ethernet Infrastructure Measurements - Switches​

https://www.open-end-music.com/foru...von-ethernet-infrastruktur-switches-nur-lesen

Use Google translate if you need help reading it.

Eric, the author of the study, investigates how noise and jitter in an Ethernet transmission can be affected by ethernet cables and various audiophile tweaks, such as switches, EtherRegen and external clocks, isolators, reclockers, and "better" power supplies, such as those from iFi, etc. Unlike most measurements on ASR that are done at the output of a DAC, Eric measures in the digital domain before the DAC.

The last post in that thread contains conclusions so far. Here's a sample (courtesy Google Translate):
1666094472603.png


PS: The title of this post is a bit sarcastic, as I think, most here would not find Eric's findings to be a huge surprise :)
 

DonH56

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Not that I have looked, but strongly suspect there is no comprehensible theory for why Ethernet "regenerators" improve the sound because there is no improvement and nobody is willing to take (or publish) DBT results.

It is possible some of these devices do not have proper galvanic isolation so ground noise is influencing the sound. But I sort of doubt it.

And there are numerous threads touting the benefits of cascading Ethernet switches to further improve the sound, complete with discussions about the types and order of switches that sounds best.

There are also comparisons of how hard drives affect the sound and so forth. Mind boggling.
 

ahofer

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We found a solution, you figure out the problem!
 
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pkane

pkane

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Not that I have looked, but strongly suspect there is no comprehensible theory for why Ethernet "regenerators" improve the sound because there is no improvement and nobody is willing to take (or publish) DBT results.

It is possible some of these devices do not have proper galvanic isolation so ground noise is influencing the sound. But I sort of doubt it.

And there are numerous threads touting the benefits of cascading Ethernet switches to further improve the sound, complete with discussions about the types and order of switches that sounds best.

There are also comparisons of how hard drives affect the sound and so forth. Mind boggling.

It's hardly surprising that in Eric's tests these so called ethernet "cleaners" actually caused more noise and increased jitter in the digital transmission. The need for an expensive outboard "low phase noise" clock to plug into an expensive Ethernet regenerator/reclocker to improve audio quality is just one idea that especially boggles the mind...
 

bloodshoteyed

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PS: The title of this post is a bit sarcastic, as I think, most here would not find Eric's findings to be a huge surprise :)

i did raise an eyebrow when seeing such a reputable users name as OP on a post title like this...
but then again, it is spooktober, right?
emoji-phew.gif
 

blueone

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Apparently these guys have never heard of CRC32 and receive-side endpoint buffering. (I did a site-wide search for "CRC", and nothing came up.) Of course, then there's IP and TCP checksums, and I've never seen a music app that is buffering less than two seconds of digital data. And it is digital data. IMO, some peoples' thought processes would benefit from an enema.
 

anotherhobby

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Of course, then there's IP and TCP checksums, and I've never seen a music app that is buffering less than two seconds of digital data. And it is digital data. IMO, some peoples' thought processes would benefit from an enema.
It's like nobody has heard of TCP or has any idea how it works or what role it plays in data transmission, even though it's been around since 1974. Snake oil for people that just don't understand how it works (which is most people). It's so proposterous.
 

voodooless

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PS: The title of this post is a bit sarcastic, as I think, most here would not find Eric's findings to be a huge surprise :)
No surprise indeed. The sad thing is that none of this needs any experimentation or testing. The way these things work already explain why they can’t possibly make a difference.
 
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pkane

pkane

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No surprise indeed. The sad thing is that none of this needs any experimentation or testing. The way these things work already explain why they can’t possibly make a difference.

Noise can be insidious and sneak in over ways that you'd least expect it to. So, while not surprising, it's still useful to have someone go through the trouble of demonstrating objectively how some of these audiophile tweaks may actually make ethernet transmission noise/jitter worse.

The effects of digital noise/jitter on the analog portion of the audio chain is likely none, but it's nice to have an objective proof that these hack products often do the opposite of what they claim.
 

voodooless

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Noise can be insidious and sneak in over ways that you'd least expect it to. So, while not surprising, it's still useful to have someone go through the trouble of demonstrating objectively how some of these audiophile tweaks may actually make ethernet transmission noise/jitter worse.

The effects of digital noise/jitter on the analog portion of the audio chain is likely none, but it's nice to have an objective proof that these hack products often do the opposite of what they claim.
It’s like shooting a flat earther to the moon to show them the earth is round… once they are back they will still find some new reason why the earth is still flat :facepalm: Same will happen here, no matter what kind of proof is presented.
 

amirm

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That's insane amount of work there! Using an old scope which necessitated taking actual pictures of the display surely added a lot to the work.

It is interesting that just like my testing, some of these devices make things that they say they do better, actually worse!
 

ahofer

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Interesting to me that, once again, adding low level noise seems to be correlated with finding the sound "more spacious". In this case, unlike vinyl/tape/tubes, it may not be audible.
 

KSTR

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I've been monitoring this thread from the beginning and do appreciate the quite professional work done by Eric... but the all important question remains: do the different RF noise levels actually manifest themselves as noise or demodulated RF or any other type of disturbance of the final analog signal?

With a lesser design of an AVR or streamer with integrated DAC it may be so (though not that easy to measure) as especially the common-mode noise may affect the analog output directly or indirectly (via "gnd pollution" etc) but that's just a hypothesis put forth with no actual proof, yet.

Still a good job on debunking some of the claims of high end ethernet cables, audiophile switches etc.
 

anotherhobby

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Still a good job on debunking some of the claims of high end ethernet cables, audiophile switches etc.
Literally all anybody needs to do to debunk these types of clamis is to take a few minutes to actually read the wikipedia page on TCP. That's it! It debunks all of it simply by the nature of how TCP works (and you can apply what you've learned to more than stupid audiophile myths). I mean, this paragraph alone drives a nail right thru it (my bolding for emphasis):
At the lower levels of the protocol stack, due to network congestion, traffic load balancing, or unpredictable network behaviour, IP packets may be lost, duplicated, or delivered out of order. TCP detects these problems, requests re-transmission of lost data, rearranges out-of-order data and even helps minimize network congestion to reduce the occurrence of the other problems. If the data still remains undelivered, the source is notified of this failure. Once the TCP receiver has reassembled the sequence of octets originally transmitted, it passes them to the receiving application. Thus, TCP abstracts the application's communication from the underlying networking details.
In other words, TCP fully reassembles all the packets BIT PERFECT (to use an audiophile term) to what came over the "wire" before any audio application ever sees it. If you are using TCP, the layers below it do not matter at all as long as the packets are coming in fast enough.
 
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pkane

pkane

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Literally all anybody needs to do to debunk these types of clamis is to take a few minutes to actually read the wikipedia page on TCP. That's it! It debunks all of it simply by the nature of how TCP works (and you can apply what you've learned to more than stupid audiophile myths). I mean, this paragraph alone drives a nail right thru it (my bolding for emphasis):

In other words, TCP fully reassembles all the packets BIT PERFECT (to use an audiophile term) to what came over the "wire" before any audio application ever sees it. If you are using TCP, the layers below it do not matter at all as long as the packets are coming in fast enough.

TCP works, but audiophile lore has also evolved and now includes various explanations for why even a bit-perfect playback may not sound good. With no real evidence, measurements, or controlled listening tests, various audiophile manufacturers started producing "cures" for these "issues". Cures that include things like ethernet clock regeneration for jitter reduction, super-capacitor power supplies for the ethernet switches to reduce PS noise and ground leakage currents, and heroic measures to add galvanic isolation into network switches and network cards. All, supposedly, to reduce the electrical noise that can travel from the source device all the way to the output of a DAC (or to the clock power supply causing additional jitter). This also resulted in expensive audiophile ethernet cables, overpriced outboard clocks, and monstrous ethernet switches that are overbuilt and overpriced for what they do, all based on faith that somehow the expected reduction in network noise will result in better sound quality.

This is the kind of stuff Eric tried to test for and demonstrated that the cure can be much worse than the disease, in some cases increasing noise and jitter by a large margin -- just the opposite of what these devices supposedly claim to achieve.
 

mansr

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This is the kind of stuff Eric tried to test for and demonstrated that the cure can be much worse than the disease, in some cases increasing noise and jitter by a large margin -- just the opposite of what these devices supposedly claim to achieve.
No surprise there. Quite the opposite, actually.
 

sam_adams

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"but...but... did you listen to it?"

Along the same line the question could be asked; did you measure the analog signal? We don't listen to 'bits' we listen to the analog reconstruction of those 'bits'. If there's no change to the analog signal, then all those devices have changed nothing except the numbers in someone's bank account.
 

DonR

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Along the same line the question could be asked; did you measure the analog signal? We don't listen to 'bits' we listen to the analog reconstruction of those 'bits'. If there's no change to the analog signal, then all those devices have changed nothing except the numbers in someone's bank account.
Maximum fidelity in the 1's and 0's.
 

MaxwellsEq

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Some streaming protocols run over UDP, rather than TCP, where the responsibility for end-to-end data error correction and ordering is the responsibility of the application. Meanwhile there's a strong move to QUIC and HTTP3.

I've done troubleshooting on large Ethernet/IP networks. It's a mistake to assume end-to-end errors don't exist. A router, for example, rewrites Ethernet headers and recalculates the checksum. I've see routers with slight memory errors corrupt the data field, then create a correct checksum for the packet.

However, everything I've seen so far in audiophile land to "fix" Ethernet is daft.

Some equipment may not have good galvanic isolation, or may be sensitive to noise, but those are flaws which should be fixed, not mitigated.
 
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