4 ms·

One thing to realize is that especially for high resolution video cables these cheap testers can't really deliver. The way to test them is a eye diagram (see: h

by atoav 7mo ago

One thing to realize is that especially for high resolution video cables these cheap testers can't really deliver. The way to test them is a eye diagram (see: https://incompliancemag.com/eye-diagram-part2/ https://incompliancemag.com/eye-diagram-part2/ ) and testers with that capsbility cost upwards of 10.000 Eurodollars.

deleted 7mo ago
[deleted]
jmalicki 7mo ago
So you're saying there is something to audiophile grade HDMI cables?
- HPsquared 7mo ago
  With digital signals and ECC, the cable need only be "good enough" to get perfect data transfer through the system.
  - jmalicki 7mo ago
    His link made very clear the issues of jitter and flickering.
    - tom_alexander 7mo ago
      These two statements aren't mutually exclusive. The link is looking at the analog signal through an oscilloscope. The person you replied to is pointing out that after decoding and applying error correction, you can still end up with the same digital signal output. So the eye diagram charts are useful for detecting the quality of the cable, but as long as the quality is past a certain threshold, it does not matter.
      - SAI_Peregrinus 7mo ago
        And that threshold is "baked in" to the eye mask pattern you load into the tester. If the eye stays out of the masked areas, it passes, if it goes into the masked areas it fails. Oscilloscopes capable of eye diagram testing can trigger on failure, so if it passes an eye test it'll reconstruct correctly with proper timing.
  - atoav 7mo ago
    Correct. But especially if you're using long cables a cable with more "headroom" in the eye diagram will perform more reliable than one that is just at the edge of breakup. For home use that doesn't matter usually, but I for example run events where I need the cable to work also after 10 people stepped on it and then this can become a significant thing. Not in terms of quality, but reliability.
- scq 7mo ago
  No. What it can affect though is the bandwidth of the cable, meaning e.g. for HDMI cables, they might not support higher resolutions or framerates. If it's on the border you might see random disconnects or screen blanks. The quality degrading is not something you will see, as it's a digital protocol. "Audiophile grade" HDMI cables are likely to just be a Shenzhen bargain-bin special with some fancy looking sheathing and connectors. I would trust them less than an Amazon Basics cable.
  - fmajid 7mo ago
    Indeed. If I want super high quality cables, I get them from Blue Jeans Cables, who tell you exactly what Belsen or Can are cable stock and what connectors, as well as the assembly methodology.
    - fmajid 7mo ago
      Belden or Canare. Pesky autocorrect.
- atoav 7mo ago
  No. What I am saying is that it is hard to test the quality of a 8K 240Hz 4444 video cable without having a device that can send and receive this or even higher. If you send bits across a line fast enough you're grtting into the territory of RF electronics, with wrong connector or conductor geometry you will get echos on the line and all kind of signal loss. A good digital protocol should keep this at bay with error correction and similar mechanisms, but if you want to know what the good cable is on a better than binary scale of works/does not, you need to look at these things.
  - jmalicki 7mo ago
    I just need to make a cable with better eye diagrams so I can market it to AV enthusiasts with "golden eyes"!
    - TeMPOraL 7mo ago
      Our cables are so good that their eye diagrams look like a photograph of a cross-section a gold analog AV connector. That is not a coincidence!
    - atoav 7mo ago
      Well the thing is better doesn't mean better quality here. Better means you can use a longer cable or abuse the cable for longer till it dies. This is a big part of what makes any pro gear expensive: reliability. If you just connect your home hifi to your speakers in an acoustically untreated space, you could also just use a bunch of steel wire coathangers and get an indistinguishable result. Even a el-cheapo store brand music shop cable will do the trick for years if you don't habitually change your setup four times a week (most people don't). But if you need reliability and predictability in a studio or live context giving a damn about cable quality is mandatory since a broken cable in the wrong place can ruin your day and reputation. But it is an absolute myth that they will affect the sound in any meaningful way. Exeption: guitar cables. The capacitance of guitar cables can shift the resonance frequency of the pickup up or down leading to audibly different results. But that id no magic either, you could just take a low capacitance cable and add in arbitrary capacitor for 10 cents as needed.
SAI_Peregrinus 7mo ago
Keysight are nice enough to provide prices on their web site for all their cheaper equipment. I priced out a setup for USB 2.0 eye diagram compliance testing on their site in this comment¹ and it's more like $40,000 than $10,000. ¹https://news.ycombinator.com/item?id=47568399 https://news.ycombinator.com/item?id=47568399
- atoav 7mo ago
  I said 10k because I think I saw a specialized product just for HDMI starting at roundabout that price bracket once mentioned in a youtube video, csn't really remember the brand, but it was relatively unknown in terms of test equipment. More generic (and flexible) equipment like the one mentioned will indeed tear a deeper hole into your pocket, but comes with its own perks.
  - superxpro12 7mo ago
    The "certified" lab-grade stuff is so expensive because your essentially paying for someone else to certify the function for you. There's cheaper generic VNA's that dont claim "yup, this is HDMI Ultra High Speed" that might work in the right hands.

by atoav 7mo ago

deleted 7mo ago

[deleted]

jmalicki 7mo ago

So you're saying there is something to audiophile grade HDMI cables?

HPsquared 7mo ago
With digital signals and ECC, the cable need only be "good enough" to get perfect data transfer through the system.
- jmalicki 7mo ago
  His link made very clear the issues of jitter and flickering.
  - tom_alexander 7mo ago
    These two statements aren't mutually exclusive. The link is looking at the analog signal through an oscilloscope. The person you replied to is pointing out that after decoding and applying error correction, you can still end up with the same digital signal output. So the eye diagram charts are useful for detecting the quality of the cable, but as long as the quality is past a certain threshold, it does not matter.
    - SAI_Peregrinus 7mo ago
      And that threshold is "baked in" to the eye mask pattern you load into the tester. If the eye stays out of the masked areas, it passes, if it goes into the masked areas it fails. Oscilloscopes capable of eye diagram testing can trigger on failure, so if it passes an eye test it'll reconstruct correctly with proper timing.
- atoav 7mo ago
  Correct. But especially if you're using long cables a cable with more "headroom" in the eye diagram will perform more reliable than one that is just at the edge of breakup. For home use that doesn't matter usually, but I for example run events where I need the cable to work also after 10 people stepped on it and then this can become a significant thing. Not in terms of quality, but reliability.
scq 7mo ago
No. What it can affect though is the bandwidth of the cable, meaning e.g. for HDMI cables, they might not support higher resolutions or framerates. If it's on the border you might see random disconnects or screen blanks. The quality degrading is not something you will see, as it's a digital protocol. "Audiophile grade" HDMI cables are likely to just be a Shenzhen bargain-bin special with some fancy looking sheathing and connectors. I would trust them less than an Amazon Basics cable.
- fmajid 7mo ago
  Indeed. If I want super high quality cables, I get them from Blue Jeans Cables, who tell you exactly what Belsen or Can are cable stock and what connectors, as well as the assembly methodology.
  - fmajid 7mo ago
    Belden or Canare. Pesky autocorrect.
atoav 7mo ago
No. What I am saying is that it is hard to test the quality of a 8K 240Hz 4444 video cable without having a device that can send and receive this or even higher. If you send bits across a line fast enough you're grtting into the territory of RF electronics, with wrong connector or conductor geometry you will get echos on the line and all kind of signal loss. A good digital protocol should keep this at bay with error correction and similar mechanisms, but if you want to know what the good cable is on a better than binary scale of works/does not, you need to look at these things.
- jmalicki 7mo ago
  I just need to make a cable with better eye diagrams so I can market it to AV enthusiasts with "golden eyes"!
  - TeMPOraL 7mo ago
    Our cables are so good that their eye diagrams look like a photograph of a cross-section a gold analog AV connector. That is not a coincidence!
  - atoav 7mo ago
    Well the thing is better doesn't mean better quality here. Better means you can use a longer cable or abuse the cable for longer till it dies. This is a big part of what makes any pro gear expensive: reliability. If you just connect your home hifi to your speakers in an acoustically untreated space, you could also just use a bunch of steel wire coathangers and get an indistinguishable result. Even a el-cheapo store brand music shop cable will do the trick for years if you don't habitually change your setup four times a week (most people don't). But if you need reliability and predictability in a studio or live context giving a damn about cable quality is mandatory since a broken cable in the wrong place can ruin your day and reputation. But it is an absolute myth that they will affect the sound in any meaningful way. Exeption: guitar cables. The capacitance of guitar cables can shift the resonance frequency of the pickup up or down leading to audibly different results. But that id no magic either, you could just take a low capacitance cable and add in arbitrary capacitor for 10 cents as needed.

SAI_Peregrinus 7mo ago

Keysight are nice enough to provide prices on their web site for all their cheaper equipment. I priced out a setup for USB 2.0 eye diagram compliance testing on their site in this comment¹ and it's more like $40,000 than $10,000. ¹https://news.ycombinator.com/item?id=47568399 https://news.ycombinator.com/item?id=47568399

atoav 7mo ago
I said 10k because I think I saw a specialized product just for HDMI starting at roundabout that price bracket once mentioned in a youtube video, csn't really remember the brand, but it was relatively unknown in terms of test equipment. More generic (and flexible) equipment like the one mentioned will indeed tear a deeper hole into your pocket, but comes with its own perks.
- superxpro12 7mo ago
  The "certified" lab-grade stuff is so expensive because your essentially paying for someone else to certify the function for you. There's cheaper generic VNA's that dont claim "yup, this is HDMI Ultra High Speed" that might work in the right hands.