An "Audiophile Grade" SSD—Yes, You Heard That Right

[Dredi]

No the light isn't digital but all the processing is digital until the light gets emitted from the pixels.

With audio the DACs output is analog, which is going to a analog pre-amp, an analog amplifier, and then the transducer (speakers or headphones). The DAC is operating in the analog domain which is why all of this matters.

And in a modern DAC all the processing is essentially digital until the signal is output to the preamplifier.

From my perspective the difference between any good DAC is going to be small to begin with so if you aren't familiar with the rest of the system and reference material its pretty close impossible. You need to be familiar with the rest of the gear, the room, and material so that means people listening on their or stuff in their own room (or at least one they are very familiar with) and with music they know well.

And still, these people can’t differentiate between good quality DACs in a controlled blind study (level matched and no other clear faults in how the test is done). Even if it is conducted with their own setups, in their own rooms with music of their choice.

 

[Steevo]

In all DACs the signal is digital until it hits the divider transistors which supply the additive voltage to recreate the sample, at that point the cable that carried the digital signal there no longer matters as CRC checks have been done and the data is either there and valid or it doesn’t work.

I’m about ready to build a wire coat hanger USB cable and get a oscilloscope to show people, but some still would be convinced their feelings are more right than science and post more about how it feels like it sounds better cause it cost more…..

 

[Deleted member 24505]

imo buy the cheapest digital cable you can. Only analogue cable quality matters. Anyone spending $120/metre for a USB cable is a retard

 

[Operandi]

And in a modern DAC all the processing is essentially digital until the signal is output to the preamplifier.

Right, the output is analog, thats the difference and thats why it matters. I think I said that several times.

And still, these people can’t differentiate between good quality DACs in a controlled blind study (level matched and no other clear faults in how the test is done). Even if it is conducted with their own setups, in their own rooms with music of their choice.

They can though, the test I linked to shows it pretty conclusively. Its a shit ton of work to do it but when you control for only the source its pretty easy to. If you put a bunch of random people in a room they are not familiar with, speakers they are not familiar with, an amplifier they are not familiar with your test is going to fail because even the difference between a mediocre DAC and a great one is small compared to flaws between very good speakers, the room interactions ect.

In all DACs the signal is digital until it hits the divider transistors which supply the additive voltage to recreate the sample, at that point the cable that carried the digital signal there no longer matters as CRC checks have been done and the data is either there and valid or it doesn’t work.

I’m about ready to build a wire coat hanger USB cable and get a oscilloscope to show people, but some still would be convinced their feelings are more right than science and post more about how it feels like it sounds better cause it cost more…..

Thats wrong because even though the cable is only transmitting digital data thats corrected its still picking up noise that is going back into the circuit (which is analog) that needs to be rejected but realistically never completely is. Thats why high-end DACs use toroidal transformer based PSUs instead of switching mode PSUs or put the clock generator as close to the DAC IC as possible. If noise and interference didn't matter in a DAC you wouldn't do anything of that because it would be a total waste of time and resources.

If your argument is that the influence isn't audible thats fine but a USB cable is still susceptible to the noise in an environment and introducing it into the signal path.

 

[Steevo]

Right, the output is analog, thats the difference and thats why it matters. I think I said that several times.

They can though, the test I linked to shows it pretty conclusively. Its a shit ton of work to do it but when you control for only the source its pretty easy to. If you put a bunch of random people in a room they are not familiar with, speakers they are not familiar with, an amplifier they are not familiar with your test is going to fail because even the difference between a mediocre DAC and a great one is small compared to flaws between very good speakers, the room interactions ect.

Thats wrong because even though the cable is only transmitting digital data thats corrected its still picking up noise that is going back into the circuit (which is analog) that needs to be rejected but realistically never completely is. Thats why high-end DACs use toroidal transformer based PSUs instead of switching mode PSUs or put the clock generator as close to the DAC IC as possible. If noise and interference didn't matter in a DAC you wouldn't do anything of that because it would be a total waste of time and resources.

If your argument is that the influence isn't audible thats fine but a USB cable is still susceptible to the noise in an environment and introducing it into the signal path.

There is a small buffer for the data that eventually becomes audio, corrections happen there removing the direct coupling to the DAC.

Your ideas are still wrong the further down this rabbit hole you go.

 

[Dredi]

In all DACs the signal is digital until it hits the divider transistors which supply the additive voltage to recreate the sample, at that point the cable that carried the digital signal there no longer matters as CRC checks have been done and the data is either there and valid or it doesn’t work.

I’m about ready to build a wire coat hanger USB cable and get a oscilloscope to show people, but some still would be convinced their feelings are more right than science and post more about how it feels like it sounds better cause it cost more…..

A coat hanger probably won’t work as a usb cable, but for spdif that would be perfect.

They can though, the test I linked to shows it pretty conclusively. Its a shit ton of work to do it but when you control for only the source its pretty easy to. If you put a bunch of random people in a room they are not familiar with, speakers they are not familiar with, an amplifier they are not familiar with your test is going to fail because even the difference between a mediocre DAC and a great one is small compared to flaws between very good speakers, the room interactions ect.

Use headphones. Everyone can bring their own. Room does not matter and the relevant parts of the setup stays the same (meaning the headphones).

Right, the output is analog, thats the difference and thats why it matters. I think I said that several times.

Even the TV’s output is analog, light that is.

 

[Operandi]

There is a small buffer for the data that eventually becomes audio, corrections happen there removing the direct coupling to the DAC.

Your ideas are still wrong the further down this rabbit hole you go.

..... You are completely missing the point. Noise picked up by a digital cable is going to affect the analog domain of the DAC. Bit correction, buffers things that happen digital domain are completely irrelevant.

Moreover you assume that digital buffers and bit correction are 100% effective which is not the case. And the accuracy and effectiveness of those measures too is susceptible to being affected by external noise.

Use headphones. Everyone can bring their own. Room does not matter and the relevant parts of the setup stays the same (meaning the headphones).

The test I linked to included both headphones and speakers.

The result; the two lower quality by sources (by spec) were statistically identified as sounding worse, it became particularly more apparent the higher up the scale the rest of the system was. In other words the better the rest of your gear was the more likely you were able to identify the differences.

Which totally makes sense given that most DACs are good and you need a system with enough resolution to reveal a difference, and goes a long way to explaining why there is a large consensus that they don't matter.

Even the TV’s output is analog, light that is.

Of course it is. We live in a analog word (until the metaverse consumes us all).

The point is with digital video the signal is bit perfect until it hits the pixels. If you were to draw an analogy to audio you would need an all digital pre-amp, and a digital amplifier (class D amps are still analog) and only the trandcucers pushing the air would be analog. That simply doesn't exist, the closest thing we have is servo subs even those are driven with a analog signal.

 

[Steevo]

..... You are completely missing the point. Noise picked up by a digital cable is going to affect the analog domain of the DAC. Bit correction, buffers things that happen digital domain are completely irrelevant.

Moreover you assume that digital buffers and bit correction are 100% effective which is not the case. And the accuracy and effectiveness of those measures too is susceptible to being affected by external noise.

USB communications - Wikipedia

en.wikipedia.org

Cyclic redundancy check - Wikipedia

en.wikipedia.org

For a DAC/amplifier the power source will introduce more errors than USB will allow before faulting out.

 

[Operandi]

For a DAC/amplifier the power source will introduce more errors than USB will allow before faulting out.

I don't even know what that means. How can power source introduce "errors".

Again you are missing the point, the USB protocol has nothing to do with anything in the analog domain of a DAC yet that is going to susceptible to noise from a digital cable.

Noise counts on the digital side as well, the nanosecond the signal is transformed from digital to analog errors can be introduced by noise.

 

[robot zombie]

I've experienced USB noise before. Nothing short of a DAC with better isolation solves it. The machine Im using now will still get squirrely with certain ones. It sounds a lot like vrms hard at work, only coming through the speakers loud and clear.

Try this... put a paper towel tube up to your mobo VRMs while the CPU is working. Even better, run RGB on a pulse mode too. I hear all that through my speakers when I plug most dacs under $200 into my PC via USB.

Worth noting, I never found a cable or dongle that touches it. Got a lot of people so sure it was anything other than what it obviously was though. The only workable solution was a better isolated DAC. Or straight up convert to something like spdif or aes. Isolation should be a natural byproduct, just by virtue of what has to happen to do that conversion.

 

[Dredi]

The point is with digital video the signal is bit perfect until it hits the pixels. If you were to draw an analogy to audio you would need an all digital pre-amp, and a digital amplifier (class D amps are still analog) and only the trandcucers pushing the air would be analog. That simply doesn't exist, the closest thing we have is servo subs even those are driven with a analog signal.

But the light is aplified in our eyes through some analog means, before the information is shot through the nerves into our brain. Why does it matter if the analog process is using electricity or not?

I’d understand your point of view if we were talking about amps or speakers, but modern DACs are essentially completely digital.

As for the point of ’electric interference’, it of course also applies to the voltage the pixels are driven at, meaning that the brightness of pixels can be affected in the same way as in a shitty DAC the audio output can be affected. Any decent DAC (and TV) is essentially immune to that kind of shit, and the interconnect cable does not matter.

 

[Operandi]

I've experienced USB noise before. Nothing short of a DAC with better isolation solves it. The machine Im using now will still get squirrely with certain ones. It sounds a lot like vrms hard at work, only coming through the speakers loud and clear.

Try this... put a paper towel tube up to your mobo VRMs while the CPU is working. Even better, run RGB on a pulse mode too. I hear all that through my speakers when I plug most dacs under $200 into my PC via USB.

Worth noting, I never found a cable or dongle that touches it. Got a lot of people so sure it was anything other than what it obviously was though. The only workable solution was a better isolated DAC. Or straight up convert to something like spdif or aes. Isolation should be a natural byproduct, just by virtue of what has to happen to do that conversion.

Yeah, I heard something like that once before on Fucusrite Scarlet, shouldn't really happen if things are working properly but clearly things can go pretty wrong.

A cable can only shield the signal from outside interference / noise. With something like this no cable is going to solve it because the noise is being conducted through the cable from the PC to DAC's analog output stage. Something is really wrong in a situation like this as you are hearing things that are not even part of the signal. Nothing really to do with how (external) noise can affect things but it illustrates a point of how sensitive the signal path really is even though its "digital".

But the light is aplified in our eyes through some analog means, before the information is shot through the nerves into our brain. Why does it matter if the analog process is using electricity or not?

Yeah, it still matters and errors could occur at the output stage of the light source or even in the final conversion of signal to analog and frankly they probably do but our panel tech isn't that great anyway and I'm not sure our vision is at the same level of acuity as our hearing to pick up on things like that even if the panels were good enough.

I’d understand your point of view if we were talking about amps or speakers, but modern DACs are essentially completely digital.

As for the point of ’electric interference’, it of course also applies to the voltage the pixels are driven at, meaning that the brightness of pixels can be affected in the same way as in a shitty DAC the audio output can be affected. Any decent DAC (and TV) is essentially immune to that kind of shit, and the interconnect cable does not matter.

They are not completely digital, they are half analog, its right in the name.

Look at the example above as to how wrong things can go with a DAC. Granted thats an extreme example of noise making it all the way through to the output stage but any kind of noise picked up (not isolated) by the cable can make its way into path and affect the analog domain. Even the digital domain is not immune to noise, errors happen all the time, its are not immune errors to just because its digital. Asynchronous clocks and FIFO buffers largely mitigate the issue but its not eliminated, thats a fact. Now can you hear the difference?, thats the part that depends.

 

[Dredi]

Look at the example above as to how wrong things can go with a DAC. Granted thats an extreme example of noise making it all the way through to the output stage but any kind of noise picked up (not isolated) by the cable can make its way into path and affect the analog domain.

ONLY IN BADLY DESIGNED PRODUCTS!

Why would you even connect the USB power on the DAC to anything? As for the USB’s digital signal, it is a BALANCED input, which negates essentially all interference BY DESIGN. You could also use optoisolators on the DACs PCB to get rid of all (theoretically)possible interference from the digital signal, but that is not necessary.

The noise you hear from bad cables when listening to badly designed DACs come from the power supply, not the USB signaling, nor the cable. Use a DAC with separate power supply, and you won’t get the ”cable interference” anymore.

Please, in the future, could you be more specific when describing things like ’the USB signal’, as you seem to mix that constantly with the USB 5 volt power output. The USB power is usually of bad quality, and shielding that does not help in most instances, as it does absolutely nothing to fix the power source itself.

Edit: and just to be clear;
There is no need to shield the power cable (unless you live inside a microwave). Go look at some topping DAC measurements. Do you think that they use shielded power supply cables, to get rid of this interference you speak of? No. And they still get some of the best SNR measurements ever on a consumer product.

the scarlett devices (in the example you quoted) use USB power, and are thus at the mercy of your power supply and motherboard. If they are shit, then you might get some interference. You can fix that by using a powered USB hub that has a stable power supply, or a USB cable with a separate power input of decent quality.

 

[Operandi]

ONLY IN BADLY DESIGNED PRODUCTS!

Yeah, thats an example of something performing really poorly due to (bad) design. I only pointed it out because it illustrates that just being a digital interface dosn't make it immune.

Why would you even connect the USB power on the DAC to anything? As for the USB’s digital signal, it is a BALANCED input, which negates essentially all interference BY DESIGN. You could also use optoisolators on the DACs PCB to get rid of all (theoretically)possible interference from the digital signal, but that is not necessary.

It mitigates it, it dosn't solve it. A digital signal transmitted over a cable happens via analog waveform and there is only so much you can do post reviving the signaling. Errors happen because you have limits on bandwidth and time when it comes to realtime audio streams.

Please, in the future, could you be more specific when describing things like ’the USB signal’, as you seem to mix that constantly with the USB 5 volt power output. The USB power is usually of bad quality, and shielding that does not help in most instances, as it does absolutely nothing to fix the power source itself.

In the grand scheme of things it dosn't matter for reasons I already mentioned. The cable its able to pick up noise that affects both the analog and digital domain both, neither are immune.

Edit: and just to be clear;
There is no need to shield the power cable (unless you live inside a microwave). Go look at some topping DAC measurements. Do you think that they use shielded power supply cables, to get rid of this interference you speak of? No. And they still get some of the best SNR measurements ever on a consumer product.

Measurements should only be used to used to verify what you hear and to aid in the design process. If you were to just go by audio measurements alone we could have stopped developing DACs 10-15 years ago, yet were still at it but maybe you think it everything beyond a certain measurement threshold is just over engineered snake oil?

 

[Dredi]

The cable its able to pick up noise that affects both the analog and digital domain both, neither are immune.

HOW???

The usb d+ and d- signals are just compared to each other and that comparison then drives a transistor that gives information to the rest of the IC whether it’s a 0 or 1 on a given time. NOT A SINGLE ELECTRON FROM THE DATA LINES IS TRANSMITTED TO THE ANALOG DOMAIN.

Yeah, thats an example of something performing really poorly due to (bad) design. I only pointed it out because it illustrates that just being a digital interface dosn't make it immune.

I NEVER STATED THAT DIGITAL INTERFACES WOULD BE IMMUNE!!!

I even had an example of a TV picture fluttering because of a bad power supply.

What I’m trying to say is that (most) digital signaling cables either work or do not. (There are examples where the devices are given power with the signaling itself, which is IMO out of scope here)

YOU are trying to somehow obfuscate shitty powersupplies with USB cables, which makes zero sense.

 

[Operandi]

The usb d+ and d- signals are just compared to each other and that comparison then drives a transistor that gives information to the rest of the IC whether it’s a 0 or 1 on a given time. NOT A SINGLE ELECTRON FROM THE DATA LINES IS TRANSMITTED TO THE ANALOG DOMAIN.

Digital 1's and 0's are represented as a polarity changes over a analog signal. Because you don't have unlimited bandwidth or unlimited time in a audio stream errors will happen and that is why noise of any kind is a factor.

OU are trying to somehow obfuscate shitty powersupplies with USB cables, which makes zero sense.

No, I'm simply saying noise from any source is an issue, it doesn't matter where it comes from. The fact that shitty power supplies are one of the most prominent and easily identifiable sources of noise changes nothing in relation to other sources of noise.

 

[Dredi]

Digital 1's and 0's are represented as a polarity changes over a analog signal. Because you don't have unlimited bandwidth or unlimited time in a audio stream errors will happen and that is why noise of any kind is a factor.

So what kind of errors are we talking about here? Jitter? Data corruption?

EMI based shit can affect only the latter, which is clearly audible if present (USB packet corruption -> missing segments of audio. There is no ’retry’ mechanism in USB audio). I.e. It either works or doesn’t.

 

[Operandi]

So what kind of errors are we talking about here? Jitter? Data corruption?

EMI based shit can affect only the latter, which is clearly audible if present (USB packet corruption -> missing segments of audio. There is no ’retry’ mechanism in USB audio). I.e. It either works or doesn’t.

Both jitter and data corruption. Errors can happen for the reasons I already stated (limited bandwidth, and the way digital audio streaming works). Buffers and error correction mitigate the problems associated with the conversion process but do not eliminate the issue. The clock signal is also carried on the same analog waveform that carries data so that too is susceptible to EMI.

Its not "works or it doesn't" thats the fallacy, you never get a perfect reproduction of the analog signal, distortion is present in the entire signal chain and presents as audible quality differences.

 

[Dredi]

you never get a perfect reproduction of the analog signal

Of course not. But it is not because of USB cables influence over the sound. What is perfect reproduction anyway? In order to quantify it, you need to measure it, and due to the duality problem in (electrical) measurements it is impossible to measure anything perfectly. Perfect reproduction of the original analog signal (as in sound waves) is already fucked when recording, as no-one knows how to make massless microphone diaphrams.

The clock signal is also carried on the same analog waveform that carries data so that too is susceptible to EMI.

I suspect that you don’t understand how USB audio transfer works. There is no clock signal, like in spdif/toslink.

 

[Operandi]

Of course not. But it is not because of USB cables influence over the sound. What is perfect reproduction anyway? In order to quantify it, you need to measure it, and due to the duality problem in (electrical) measurements it is impossible to measure anything perfectly. Perfect reproduction of the original analog signal (as in sound waves) is already fucked when recording, as no-one knows how to make massless microphone diaphrams.

Perfect would be no measurable or audible difference. And there is a difference between what can hear and what you can measure. If you are in the camp that believes things like Audio Precision are the be all end all in audio analysis and tells us all there is to ever know then there probably isn't much more to really discus.

The (USB) cable is active component, physics dictates its going to have an influence for all the reasons mentioned already. You can have the opinion that the whatever differences are are not audible, but they exist.

I suspect that you don’t understand how USB audio transfer works. There is no clock signal, like in spdif/toslink.

Yeah there is. All DACs have a clock that has to be maintained with the source. USB has different ways to go about it depending on the DAC and OS and driver combination though.

 

[Dredi]

Yeah there is. All DACs have a clock that has to be maintained with the source. USB has different ways to go about it depending on the DAC and OS and driver combination though.

Almost all mediocre quality and up USB DACs have an internal clock only (when listening to music anyway, computer games might be different). They request data from the source. Go read up on asynchronous USB audio.

Perfect would be no measurable or audible difference. And there is a difference between what can hear and what you can measure. If you are in the camp that believes things like Audio Precision are the be all end all in audio analysis and tells us all there is to ever know then there probably isn't much more to really discus.

The (USB) cable is active component, physics dictates its going to have an influence for all the reasons mentioned already. You can have the opinion that the whatever differences are are not audible, but they exist.

I agree that audibility is the only thing that really matters. USB cables do not partake in that.

Blind studies show that hardly any of ’high-end’ audio crap has any meaning at all when it comes to audibility. USB cables or m.2 SSD:s definitely do not.

The USB cable is not an active component, but a passive one. It has no electronics inside it.

Passive Component

This definition explains the meaning of Passive Component and why it matters.

www.techopedia.com

Physics also dictate that the way you breathe across the globe has an effect on the music I listen to right now. Is that relevant to anyone? No.

You are free to disagree and to
be wrong.

 

[Operandi]

Almost all mediocre quality and up USB DACs have an internal clock only (when listening to music anyway, computer games might be different). They request data from the source. Go read up on asynchronous USB audio.

There are clocks on both sides, it just depends on which side is the reference clock. Windows doesn't even support asynchronous USB audio without a third party driver.

I agree that audibility is the only thing that really matters. USB cables do not partake in that.

Blind studies show that hardly any of ’high-end’ audio crap has any meaning at all when it comes to audibility. USB cables or m.2 SSD:s definitely do not.

The USB cable is not an active component, but a passive one. It has no electronics inside it.

Because its able to pickup interference its prone to distorting the signal and causing errors its active. Error correction and buffers mitigate the issue but do not eliminate it ,that makes it audible. In that sense its an active component in the system, I didn't mean to imply it was powered.

Blind studies with this kind of thing hard to do with proper control. Without proper control you are not really getting any useful data and your conclusions are only as good as the data. I already linked to one that shows pretty conclusively you can pick out the differences between sources pretty easily when the rest of the system is good enough. A cable is going to have less of an influence than a changing out one source for another but if something is prone to producing errors and affecting the sound (which it is) who are you to say that someone can't hear the difference between one cable and another?

You are free to disagree and to
be wrong.

Yep, you too.

 

[Dredi]

Windows doesn't even support asynchronous USB audio without a third party driver.

It has for at least ten years. Maybe think about upgrading.

Because its able to pickup interference its prone to distorting the signal and causing errors its active. Error correction and buffers mitigate the issue but do not eliminate it ,that makes it audible. In that sense its an active component in the system, I didn't mean to imply it was powered.

So your wallpaper is also an active component? It can affect how your display draws power, which can cause ripple to the power lines in your house, which can propagate through your DAC’s power supply to the ’analog side’ of it.

Now that you know that your wallpaper affects your music experience, do you advocate for ’high-end’ wallpapers?

Just by knowing that timing inaccuracies are present does not make them audible. Audibility needs to be proven.

Blind studies with this kind of thing hard to do with proper control. Without proper control you are not really getting any useful data and your conclusions are only as good as the data.

Yes, and without blind studies you have no data.

I already linked to one that shows pretty conclusively you can pick out the differences between sources pretty easily when the rest of the system is good enough.

Yes, a meaningful amount of people could pick out a crappy 10 year old motherboard audio out of other options. That has nothing to do with USB cables.

 

[Operandi]

It has for at least ten years. Maybe think about upgrading.

It used to be a Mac and Linux thing only unless you had proprietary driver. It looks like MS snuck class 2 USB audio support into Windows 10 with one of the creator updates though a while back.

Either way its a recent change in how Windows handles USB audio and I don't think its the default even if you have support for it. Unless you know otherwise.

So your wallpaper is also an active component? It can affect how your display draws power, which can cause ripple to the power lines in your house, which can propagate through your DAC’s power supply to the ’analog side’ of it.

Now that you know that your wallpaper affects your music experience, do you advocate for ’high-end’ wallpapers?

Am I supposed to take this seriously? A cable that is prone to interference and producing errors is a real thing.

Just by knowing that timing inaccuracies are present does not make them audible. Audibility needs to be proven.

Proven to whom and how? Measurements don't tell you everything and often conflict or show no difference with what you hear to be superior or inferior. We have a long way to go in terms of getting a complete picture with audio measurements. Measurements are a tool to confirm what you hear, nothing more.

Blind studies sure, but its an insane amount of work to do properly. Its a ton of work to even do improperly (not enough controls) and draw incorrect conclusions from it.

From my perspective what x number of people are able to hear from one component change out of a given sample is kind of pointless when there are so many other variables. I'm more interested in why something could make a difference and understanding why and then hearing for myself. Blind studies, measurements, specsheets are interesting but even if those things were completely conclusive it dosn't meaning you or I are going to hear what they are purporting to prove.

Yes, and without blind studies you have no data.

To that I would just say absence of proof is not proof of absence.

Yes, a meaningful amount of people could pick out a crappy 10 year old motherboard audio out of other options. That has nothing to do with USB cables.

Most picked out the onboard audio (which had pretty decent specs) on a pretty wide range of gear. If you read further into the test people that had higher end gear were able to hear differences between the higher-end sources as well.

 

[Dredi]

To that I would just say absence of proof is not proof of absence.

And you can’t prove a negative.

If you read further into the test people that had higher end gear were able to hear differences between the higher-end sources as well.

I did read it. No goup got even close to the loose p=0.05 criteria for picking out anything but the 10 year old crappy motherboard. If you are saying otherwise, at least link to the correct place in the ’study’.

It used to be a Mac and Linux thing only unless you had proprietary driver. It looks like MS snuck class 2 USB audio support into Windows 10 with one of the creator updates though a while back.

Async usb audio was present since at least 10 years, with the default driver (since windows vista). It is part of even the class 1 USB audio.

Measurements don't tell you everything and often conflict or show no difference with what you hear to be superior or inferior. We have a long way to go in terms of getting a complete picture with audio measurements. Measurements are a tool to confirm what you hear, nothing more.

Exactly. This is why blind studies are the way to go.

Am I supposed to take this seriously? A cable that is prone to interference and producing errors is a real thing.

Why wouldn’t you take it seriously? The audible effects are, for all we know, in the same range as the USB cable differences. Absense of proof is not proof of absense.