Jinjuku 9-14-2017
... I’ll stand pat on a properly constructed, passes spec, Blue Jeans CAT6 vs a boutique cable that also passes spec and similarly constructed. And when I say of similar construction I’m talking the shield if any and how it’s connected (or not). It should be noted that in most cases of sonic differences that have been reported here the comparisons were between cables differing in Cat number or shielding (or lack thereof) or both, and therefore presumably in terms of various other electrical parameters and construction details as well. Regards, -- Al |
Jinjuku 9-14-2017
People that are discerning these differences are describing real time phenomena to a non-realtime system of data transmission. It is 100% delusion pure and simple. This assumes that all of the circuitry that is involved performs in an idealized manner, meaning that effects of the non-real time signals and circuitry on the downstream real time circuitry are zero, carried out to many decimal places. As an experienced designer of high speed digital and analog circuitry (for defense electronics) I can tell you that is often not the case. For further explanation see my post in this thread dated 3-27-2017. Also, while my own system does not utilize an ethernet connection, the many posts that have been made here over the years by members such as Grannyring, DGarretson, Bryoncunningham, and others who have reported finding audibly significant differences among inexpensive ethernet cables warrant a great deal of respect for their reported perceptions, IMO. That respect coupled with the technical hypothesis I stated in my 3-27-2017 post leads me to emphatically disagree with your assertion that they are delusional. Regards, -- Al |
Jinjuku, I'm referring to jitter at the point of D/A conversion, within the DAC component. If the explanation for the reported differences that I stated in my post dated 3-27-2017 is correct (and both I and Shadorne have stated that we cannot conceive of any other possible explanation, assuming the reported sonic perceptions are correct), it **does** have to do with the ethernet cable, **even though** the signals being conducted by that cable ostensibly have no relation to the timing of D/A conversion.
Careful reading of my 3-27-2017 post should make what I am saying clear.
Regards,
-- Al
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Hi Shadorne,
As you know I’ve agreed with many of your posts in the past, that are often very informative, and I always view them with respect even when I disagree. In this case we’ll have to agree to disagree.
When highly experienced audiophiles such as DGarretson, Grannyring, and Bryoncunningham, all of whom have excellent systems as well as exceptionally high credibility in my book, report that changing from one inexpensive ethernet cable to another inexpensive ethernet cable results in significant sonic improvement, IMO a suggestion that they should get rid of one (and perhaps both) of the components that the cable is connecting amounts to an extreme position. And even more so given that there would seem to be no particular basis for confidence that whatever replacement is chosen would be any better in that respect, and might be worse in that or any number of other respects.
Also, regarding ... ... we should be completely justified to expect that good audio gear should be immune from small changes in Ethernet wiring. ... from a design standpoint I’m not sure that what you are saying we should be able to expect is as easily accomplished as you are envisioning. For example, in a post in this thread dated 3-28-2017 I suggested the following experiment to some of the others: Tune a portable battery powered AM radio to an unused frequency, with the volume control set at a position that you would normally use. Bring it close to an unshielded ethernet cable on your LAN, while the cable is conducting traffic. You may be surprised at what you hear. When I do that with the unshielded Cat5e cable I have on the LAN in my house, while the cable is **not** conducting any large amount of traffic, I hear increases in static from the radio when it is as far as 2 feet from the cable. Keep in mind that an AM radio is designed to just be sensitive to a narrow (~10 kHz) range of frequencies in the lower part of the RF region (nowhere close to frequencies corresponding to the bit rate of ethernet traffic, much less to the frequency components that constitute the risetimes and falltimes of the signals), and to have a sensitivity measured in microvolts. And for audio we’re dealing with microvolts as well, but without the benefit of the radio’s narrow band filtering. For digital audio if 2 volts corresponds to full scale the least significant bit of a 16 bit word corresponds to about 30 microvolts. And the least significant bit of a 24 bit word corresponds to about 0.1 microvolts! And perhaps more significantly there are jitter effects that will arise as a result of noise whenever D/A conversion is performed, of course. And this experiment just involves radiation of RFI through the air. Not through what would seem likely to potentially be much more significant unintended pathways for digital noise, such as grounds, other wiring, and parasitic capacitances within the components.
Regards,
-- Al
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Yes, I did forget that one, Geoff. Thanks for pointing that out. But sometimes common sense and technically supportable middle-ground positions seem to get overlooked in disputes between those at opposite extremes of the belief spectrum.
Regards,
-- Al
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Shadorne, I partially agree and partially disagree with your latest post above. I agree that sensitivity to ethernet cable differences is a manifestation of less than ideal behavior by the components that are involved. And in at least some cases might be an indication that the designer's expertise is less than ideal. However arguably no design is perfect, and all designs represents the net result of countless tradeoffs, including practical ones such as cost. (And by that I am not referring just to production costs, but to development costs, time constraints on the development process, etc). So components having less sensitivity to differences in that cable may very well have any number of countless other downsides that are conceivable, in comparison with competitive products that are more sensitive to those differences.
Regards,
-- Al
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I don't doubt or question the comments in your post just above, Jinjuku. I have said in many previous threads here that the musical resolution of a component or system, and its sensitivity to and ability to resolve hardware differences, are two different things. And in a reasonably high quality system the correlation between the two, while certainly greater than zero, is also a good deal looser than many audiophiles seem to believe.
Regards,
-- Al
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So if really expensive equipment is actually susceptible to this then the EE’s that are designing it don’t know what they are actually doing. They may want to re-read Ott. It wouldn’t surprise me if many audio designers have not read Ott. Or studied the aptly named book "High-Speed Digital Design: A Handbook of Black Magic." (My background, btw, is in defense electronics, and I have taken Mr. Johnson’s related course). Why would it matter what the source is sending if you have disconnected it at the client? These are buffered (FIFO) systems and the audio is still playing. Because as I indicated in my 3-27-2017 post possible pathways by which RFI may find its way from the cable to circuit points that are downstream of the ethernet interface include radiation into power wiring, or into other cables, or directly into various circuit points within the DAC or other components. And the degree to which that may occur may be affected by the bandwidth, shielding, and other characteristics of the cable being used. Also, perhaps a difference would occur because noise generated by the ethernet interface circuitry at the receiving end (i.e., in the DAC) may change as a result of having nothing connected to it. As far as I can recall, everything that has been said in this thread by those who deny that the reported sonic differences are real has focused on the robustness and accuracy of ethernet communications. While ignoring or discounting what I would consider, based on my experience, to be the very real possibility of interactions between signals and circuits that are ostensibly unrelated. Designs should not be assumed to behave in a manner that is theoretically ideal, IMO, and signals should not be assumed to only follow their intended pathways. Regards, -- Al |
When playing back audio and you pull the Ethernet cable, and of course it will still play back (with most systems) for a few seconds, DOES THE SOUND IMPROVE? It’s really a simple question and yet for some reason... I don’t have an ethernet connection in my audio system, so I can’t answer that based on experience. However, assuming (as I do) that the several highly experienced and widely respected audiophiles who have reported realizing significant sonic benefits by changing from one inexpensive ethernet cable to a different inexpensive ethernet cable are correct, and if the explanation of those benefits that I hypothesized in my post in this thread dated 3-27-2017 is correct, the sound may or may not improve depending on the specific system. As you will realize in reading that post, and if my hypothesis is correct, whether or not the sound improves would depend on the path(s) by which, and the degree to which, electrical noise and/or RFI from the signals in the cable reach and affect downstream circuit points that are ostensibly unrelated to the ethernet interface. It would also depend on how the content of the signal sent into the cable by the source component changes when the cable is disconnected, as a result of that component having nothing to talk to at the other end. While what I stated in my 3-27-2017 post is only a hypothesis, as an EE experienced in the design of high speed digital circuits that operate in close proximity to sensitive analog circuits and D/A converter circuits it is the only means I can envision that would account for the reported differences. And I don’t think that most of those who have similar circuit design experience and are also reasonably open minded would rule out the possibility I have stated. Regards, -- Al |
Azbrd and Dynaquest4, note that the effects (or at least the potential effects) that I described in my previous post have absolutely nothing to do with proper or improper communication of 1s and 0s.
May I suggest a simple experiment that you may find to be informative: Tune a portable battery powered AM radio to an unused frequency, with the volume control set at a position that you would normally use. Bring it close to an unshielded ethernet cable on your LAN, while the cable is conducting traffic. You may be surprised at what you hear. Then please re-read my previous post.
If you have seen many of my posts in other threads at this forum, you will realize that I am with you in believing that benefits allegedly provided by **some** controversial tweaks or other products are likely the result of either expectation bias, experimental methodology that is not adequately thorough, or failure to recognize and control extraneous variables. Not in this case, however.
Regards,
-- Al
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As an electrical engineer having extensive experience designing high speed digital, analog, A/D converter, and D/A converter circuits (not for audio), I don’t find the reported differences to be either surprising or mysterious. And I consider them to be well within the bounds of established science and engineering.
Most likely what is happening is that differences in the characteristics of the cables, such as bandwidth, shielding, and even how the pairs of conductors that carry the differential signals are twisted, are affecting the amplitude and spectral characteristics of electrical noise and/or RFI that finds its way via unintended pathways to unintended circuit points "downstream" of the ethernet interface in the receiving device. "Unintended circuit points" may include the D/A circuit itself, resulting in jitter, and/or analog circuit points further downstream in the component or system, where audible frequencies may be affected by noise that is at RF frequencies via effects such as intermodulation or AM demodulation.
"Unintended pathways" may include, among other possibilities, grounds within the receiving device, parasitic capacitances, coupling that may occur into AC power wiring, and the air.
What can be expected regarding such effects, however, is that they will be highly system dependent, and will not have a great deal of predictability.
Regards,
-- Al
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Thanks, Doug. Those reading this thread may wish to also read a series of posts beginning around 2-16-2012 in the following thread: https://forum.audiogon.com/discussions/shielding-components-from-emi-rfi-help-pleaseMember Bryoncunningham, who IMO is an especially astute and perceptive listener, and is very thorough in his evaluations, described realizing a substantial sonic improvement by changing from a garden variety unshielded ethernet cable to an **inexpensive** shielded type. I described some technical effects which may have accounted for that. Also, this thread will be of interest: https://forum.audiogon.com/discussions/are-my-cat5-and-router-my-weak-linkA comment Bryon made on 8-7-2012 in the latter thread: I can confirm what Al has reported about my experiences when I replaced an unshielded Cat 5 cable with a shielded Cat 6 cable. The result was more resolution. A lot more.
The $7 shielded Cat 6 cable resulted in a bigger improvement in SQ than several $1,000 power cords and several $2,000 interconnects. Yes, I know that sounds crazy. I can’t explain it.
I’m not saying that other systems will benefit similarly. In fact, I doubt it. But it’s certainly an affordable experiment. As I’ve said in a number of past threads, the existence of differences does not necessarily mean that more expensive = better results. Regards, -- Al |
