Gold Cables Really Do Work The Best

As a writer, I have long harboured a dream that one day an editor will buy me a top-of-the-range audio analyser, and I can set up an audio test lab and write pieces debunking the spurious claims made by audiophiles, HiFi journalists, and the high-end audio industry about the quality of their products. Does that amp really lend an incisive sibilance to the broader soundstage, and can we back that up with some measurable figures rather than purple prose?

An Audio Playground You Didn’t Know You Had

An Audio Precision APx525 audio analyser.
An Audio Precision APx525 audio analyser. Bradp723 (CC-BY-SA 3.0)

Sadly Hackaday is not an audio magazine, and if Mike bought me an Audio Precision he’d have to satisfy all the other writers’ test equipment desires too, and who knows where that would end! So there will be no Hackaday audio lab — for now. But that doesn’t mean I can’t play around with audio analysis.

Last month we carried a write-up of a Supercon talk from Kate Temkin and Michael Ossmann, in which they reminded us that we have a cracking general purpose DSP playground right under our noses; GNU Radio isn’t just for radio. Once I’d seen the talk my audio analysis horizons were opened up considerably. Maybe that audio analyser wouldn’t be mine, but I could do some of the same job with GNU Radio.

It’s important to stress at this point that anything I can do on my bench will not remotely approach the quality of a professional audio analyser. But even if I can’t measure infinitesimal differences between very high-end audio circuitry, I can still measure enough to tell a good audio product from a bad one.

Making An Audio Analyser From A Software Defined Radio

My single-frequency THD+N analayser flowgraph in GNU Radio
My single-frequency THD+N analayser flowgraph in GNU Radio

For my ersatz audio analyser I decided to keep it pretty simple, and measure only the total harmonic distortion, or THD. Strictly speaking I’m measuring THD plus noise, but in the context of experimentation this does not concern me. THD is expressed as a percentage, and it’s generally best thought of as the percentage of the signal emerging from a device under test that is due to the distortion present in the device. Thus a theoretical perfect device has a THD of 0%. The simplest way to measure THD is to inject a single frequency on the device input, then to divide what remains on the output when that frequency is filtered out by the component of that frequency present on the output. This requires a set of extremely good filters, hard work in analogue circuitry but a simple task in GNU Radio.

The flowgraph I came up with is a pretty simple one: a low pass filter cuts off just above the injected frequency while a high pass one cuts in just above that to give me the harmonics. Then it’s a simple case of mathematics to derive my % THD reading.

I’m using opposite channels of my stereo sound card as input and output, and if I hook them directly together I retrieve a THD figure with a 1kHz input of 0.0024%. Thus I’ve measured the THD of a Dell soundcard, and while it’s not as bad as it could be, for comparison a unit pitched at audiophiles would boast an extra couple of leading zeros. But of course, I haven’t just measured the THD of the soundcard.

While in theory the all-digital signal path of GNU radio is distortion-free, in fact it introduces distortion of its own. There is quantisation distortion, and distortion induced by imperfections in the filters, and then of course there is noise coming from whatever else a computer running a multitasking desktop operating system is doing. A good example came when I took the screenshot of the flowgraph, immediately the THD jumped by a factor of ten for a short time. There is a really good reason why that professional audio analyser costs so much, and why we don’t use commodity soundcards to do the job instead.

Are Gold Cables Really Better?

For 99 quid this had better be good!
For 99 quid this had better be good!

Having an audio analyser to play with, albeit a not very good one, I cast around for a test subject to try with it. The obvious thing to do was to try a comparative test, and so to that end I dropped in a couple of orders for cables. Is there any truth in the claims of upmarket cable manufacturers, or is it simply snake oil designed to part the customer from their hard-earned?

I picked up a pair of 3 ft USB cables, extremely different ones from opposite ends of the market. One was a £4 ($5) Amazon Basics cable such as the one you are probably using to charge your phone, while the other was a £99 ($123) Gold Reference Series cable from Grundlagen Audio in Germany which its manufacturer claims through its gold plated Active Quantum Nanoparticle construction delivers an exceptionally low THD for digital audio transfers compared to that of conventional cables. What could I do, but hook each cable up in turn and give it a go?

Out of the box, both cables were of near-identical length and weight, but the Grundlagen was noticeably stiffer than the Amazon cable. Probably all that extra gold isn’t as flexible or something. I used the flowgraph linked above, but with a USB sink and source replacing the audio ones. I’d expect the THD figures to be significantly lower with this arrangement because of course I will have removed my poor-quality sound card from the equation. So in with the first cable, starting with the Amazon Basics cable in a loopback from USB port to USB port. Immediately I was able to measure a respectable THD at 1 kHz of 0.00014%, not surprising given the lack of a sound card. Very good, but what about the cable costing twenty times as much? In went the Grundlagen, and straight away the difference was clear with a 1 kHz THD of 0.00007%, half that of the Basics cable. Can you hear a difference when the number is that small? Probably not, but it does prove that a gold cable is better than a grey one even if they sound the same.

The folks at Grundlagen were kind enough to share a video with us showing how they manufacture their cables. Meanwhile should any of you wish to take the idea of an audio analyser in GNU Radio any further, we’re all ears.

87 thoughts on “Gold Cables Really Do Work The Best

  1. The really funny thing about Audio, is that everything is subjective, as everybody has different taste. There is something to be said for buying a piece of gear that has the best possible THD, and so on, but in the end, if you don’t like how it sounds, it doesn’t hold much water!

      1. Most “directional audio cable”s I have seen are unbalanced with a shield. In that case you would want the shield to terminate only at the lower impedance end, which would generally be the source end. That would allow for less noise to be injected. In other words, the cable is directional.

        1. If you shield from the source end surely the entire cable then acts as a sink for any passing EM? (this almost sounds as bad as the idea of a directional cable in the first place..)

          1. Actually, having the shield connected at only one end is done in some cases to prevent ground loop issues. It’s known as ‘telescoping the shield,’ but is mainly done with balanced cables. I have seen ‘directional speaker’ cable that was unshielded and that is definitely BS.

      1. Yes, that’s great but could you tell me what gold spraypaint offers the best audio quality when you soak your cables with it? Should I over-spray and get dribbles like the ones in the photos just to make sure I get enough gold on there?

        1. I think they have “gold” and various other blinged out options in 7/11 stores in North America, probably not so much the micro now, probably all USB-C and Apple

  2. Someone has to explain this to me. DtoA on one end, digital cable transferring the data to àn AtoD and some how the cable transferring the D between the two circuits can change the THD?

    I gotta believe the equipment warmed up or something got bumped between tests. I don’t believe the cables made a difference.

    1. I thought it was interesting that they were able to measure the THD with enough precision to determine (and presumably reproduce) 0.00007%.

      But… then I saw this: “I picked up a pair of 3 ft USB cables”

      And then I looked around and couldn’t find the part where the author said “Yes I know these are USB cables, and yes I know they carry purely digital signals in no way affected by cable quality above ‘adequate’, but I’m doing this exercise to demonstrate there may be value in Gold cables for Analog signals.”

      And then I was sad.

        1. I did. It’s a fascinating factory tour. I’m pretty sure the metallic flake in the acousta-sonic outer gold coating acts as a reflector somehow to keep more of the signal inside the sheath. I’m not an audio engineer, but the entirety of my 45 minutes of Google searching has made me pretty close to one… Perhaps a physicist with a couple additional hours of Google search experience can elaborate more?

      1. The plating on the cable is irrelevant of course. Everyone knows that a proper cable must go through an extensive “aging” and “burn in” process. If you are not paying 100x the cost of copper wire you are still just an audio (and video) amateur regardless of the plating on the cable.

      1. Actually no; the social engineering project began back in mid January or mid November depending on which news service you listen to.
        but…….
        we are here to talk about power combiners, there are a lot of traps laid out there for young players.

        1. They’re referring to it being an April Fool’s post, not whatever you’re referring to. At least two HaD writers have chimed in to mention this above your comment.

  3. These BS “high quality” “audiophile grade” cables for digital signals really grind my gears. This article could’ve been a bit more scathing towards products like this. And this USB cable is clearly part of these BS products…

  4. So what’s the upper bandwidth of the high pass filter? And I’d be curious to see the frequency spectrum before the RMS block to see each frequency.
    The reason the ‘gold’ cable is better may just be because it has better shielding, which would explain that it is stiffer.
    In terms of dB, half as much noise is -3dB, and I would be surprised if anyone could hear that. But then again, with audiophiles you never know.

  5. Will their be a part 2 where you test analog audio cables?

    I’ve heard many ridiculous claims over the years, including regarding things like $10,000 “oxygen-free” speaker cables, hyper-expensive RCA cables, and other asinine products aimed at people with more money than brains. My supposition is that good electrical connections and low cable impedance would go a lot further to improve audio quality than using hyper-expensive wires that cost more than a decent used car. It would be really cool to see that sort of thing analyzed as well.

    Comparing gold-plated with silver plated connectors would be interesting also. I’ve noticed that the best RF connectors are silver plated, not gold plated, and I remember reading somewhere that gold isn’t really a great conductor but is used in some audio gear because it is exceptionally resistant to corrosion.

    1. I’ve recently had some hearing tests, and have come to the conclusion that the measurement equipment is better than my hearing could ever be.

      So my response to the “golden ears” is that if you can’t measure the difference between two cables with high quality measurement equipment, there isn’t any. Same with tube vs solid state amplifiers. There are differences, but they are measureable, One is not objectively “better” than the other, except as regards individual preference.

      1. Well, at a fundamental level light and RF are the same, but most of us here would probably consider them different in a practical sense. With that in mind, I submit that TOSLINK connectors are not actually intended for RF (I could be wrong, I have never used one). Also, RF connections at wavelengths larger than microwave typically need an electrically conductive path (usually coax), as the waveguide needed for say 150 MHz radio would be immense (would that even work? I don’t know, not my specialty).

  6. Umm…yeah. If you look at the plethora of tests that have been done on this subject with real audio analyzers being used, the conclusion is always the design of the DAC, it’s supply, and board layout. To one such study: “Even a cheaper DAC like Behringer shows that such sensitivity is due to poor DAC design than anything to do with USB cables.”
    Hmm…anybody remember rosewood audio bricks (rosewood covered lead blocks said to absorb mag fields around the power transformer in your power amp) and $30 outlet plates with gaskets that prevent audio escaping into your wall. ;)

    1. even worse: I’ve once read an audiophile claim that using a silver POWER cable made his setup sound better. Seriously – what about the countless metres of copper cable between the wall socket and the house switch board?

      1. Or the dirty overhead aluminium cables and equipment all the way back to the power station…..

        Now what would be interesting is a comparison between an amplifier running from mains power compared to the same amp with the transformer removed and instead running from some high capacity batteries of the correct voltages.

  7. Since these cables are hand made in the finest UK facility I can fully understand the incredible improvement. I would love to see annother article covering the additional security benefits of gold cables.

    1. Indeed. Is it a reference to a ground-layer that has been added by the gold coating. Or is it more reference to the fundamentals of electronics and physics this cable manufacturer ignores for the sake of marketing?

      (Yes, i know Jenny just had a fun day… :) )

  8. Gold cables likely are optimal, but then reality rears its ugly head. After use much of the gold plating is gone, and you are down to the nickel plating that I hope they put on under the gold.

      1. Let’s see… I have friends who have guitars that are more than 60 years old, that still have nickel plating on the jacks. So, when will the harder nickel plating wear down to again be gold?

    1. I once worked for a purely commercial division of a conglomerate that had everything from military to pure consumer product divisions. Many of our “engineers” came out of the military-aerospace part of the company and didn’t bother to learn what might be different in the commercial arena. I “inherited” them when I took a job as engineering manager.

      Those idiots were specifying not only gold-plated edge connectors on the PC boards, but RHODIUM_OVER_GOLD just to make the boards super expensive. The rhodium is to deal with severe fretting corrosion, which could occur when any of our purely commercial products happened to be heading off on a tank mission or a missile launch of some sort.

  9. I know the article is a joke, but there actually is a use for the high end audiophile double, triple or quadruple shielded USB cables. They work very well at isolating PC noise from SDR hardware. But obviously not gold, that is just for fools.

    Oh and high end 24-bit audiophile sound cards can make good receivers for ELF (3 Hz to 30Hz), SLF (30Hz to 300Hz), ULF (300Hz to 3kHz) and VLF (3–30 kHz) after you add an 8kg (18 pound) H-field copper coil antenna with a mu-metal core, with an extremely low noise amplifier. At these frequencies you do actually need a crazy amount of dynamic range because there is so much man made noise.

  10. I have a buddy who is an analog synthesizer snob. I build synths out of whatever sounds cool. One day he came to visit and I demonstrated the new synth I had just finished. After a bit of noodling and fat filter sweeps he remarked ‘It’s about time you built a totally analog synth- this sounds incredible!’
    When I cracked open the enclosure to show him a lone Arduino Nano the look on his face was priceless.

  11. Audiophilia nervosa is a disease that is emotional in nature. No amount of numerical data will ever convince the afflicted that their expensive stuff performs no better than the cheap stuff. Psychiatry is what’s needed here, not engineering.

    That said, some of the high end audio gear is very artistically assembled and may be worth the extra $ on that basis.

  12. Or did you prove that a better made cable is better than a lousy one?
    I don’t think that it is really a “gold” cable, just a gold plated one. And was it the cable or the connectors?

  13. The real mystery is what is it about the gold plating on Monster cable connectors that make them shear off in musical instruments when you try to unplug them? Does the otherwise inert gold plating spontaneously combust with the cable sheath? Would the $100 of cotton paper you would have otherwise had in your pocket if you bought a reasonably priced generic act as an inverse-catalyst to prevent this reaction in other lesser audio quality cables?

  14. Date noted.
    I used to work in a Hi-Fi store. Cables were by far the highest margin product we sold. Audioquest cables with little aaa batteries strapped to them were my favourite. Faux velvet lined boxes and everything.
    I have boxes of high end coax with silver conductors, gold plated everything. All targeted at coax digital links. Hilarious.
    One set claimed to use a HDPE liner to keep the helium infusion in some deeper level of insulation from escaping. For the life of the cable. Bet the helium industry would love to get their hands on that long term storage solution.

    Laughed all the way to the bank on commisison day. Suckers.

    Keeping gnarly electrical noise away from your setup while making sensible decisions around speakers, amps and signal processing kit is by far the best bang for your buck.

    These days I’d just look for a better dac – even a decent integrated amp and DAC combo.

    If you’ve ever been to a loud concert, used a power tool or are over 50 just get sonos and be done with it :p

  15. I’ve got this idea for a specterally pure amplifier that uses connectors that have been purified by been passed through the digestive tract of a a Tibetan Mystic. Based on my current market research (adds in a HiFi magazine) A 5W class ABS single channel amplifier should retail for around $5432.10.

    The incredible balance between the left and right channels is realized primarily due to the reduced amount of cash in your wallet allowing your posture to be equalized aligning your ears to the sound source.

    1. Ohhhhhhh…. that’s why I never fell for this crap.. one of my ears is naturally higher than the other, so keeping a full wallet on my hip actually has me evenly balanced.

    1. A few years back the computer expert guy on our state public radio station, assured a caller that the benefit of gold cables was that gold was the best electrical conductor of any metal. Of course, he was wrong. Silver is the best electrical conductor followed by copper, then gold. Gold is great for protecting the underlying metal from corrosion. But other than that it just costs more.

        1. Now I’m wondering if any Hifi companies have tried selling superconducting cables:
          “Yes, I do need to constantly top up the liquid helium and nitrogen, but it really opens up the soundscape!”

    1. It’s like the thing with ceramic brake pads, the pads last forever but the rotors wear through in 18 months. So the cable lasts forever but the sockets fatigue fracture their solder joints.

  16. Can’t be bothered to read all the comments on an April 1 post, but for budget audio analysis you can use an inexpensive USB interface (M-Audio or crap like that) and free software called REW (Room Equaliz[s]ation Wizard). There is a lot of info on using such a setup over at GroupDIY.com I have access to a 5000 series AP as well as an older Amber 5500 and various other test gear and I can say that the REW setup is pretty damn impressive.

  17. Pretty obvious that the thicker cable would have better signal quality. Thicker wires = lower impedance in power supply = less noise.
    The Gold-Helium-Unobtanium alloy has no effect. April fools!

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