Brilliant video. Thorough and well done, really shows the effects of imperfect USB audio protocol and translation into analog differences.
Obviously even though there are measurable effects, in the end everyone has to decide subjectively if it’s worth it in their system and which one they like. But for all naysayers that claim perfect 1s and 0s… well, they’re wrong.
I have the Supra cable and think it’s great. The fact that it has official USB spec (90ohm), power and data wires are shielded separately and cost isn’t crazy makes it worth it (for me) over the budget cables.
Before taking this video too seriously, consider the “semi-scientific” nature of the test. Also see the methodological critiques in the comments at Youtube.
Agreed, not perfect, but it’s a good attempt to show the effect compared to most subjective reviews.
I guess if he had a way of merely showing D->D transmission differences… but then folks would still have the same critique of temporal alignment.
Several manufacturers have come up with stuff to help USB signal transmission. Ifi, Matrix, Sonore, Uptone, and Schiit to name a few. USB converters to i2s are pretty cool if your DAC/preamp will accept i2s signal.
There was a flurry of posts on this topic late last year.
I posted my own findings here, which generated a few replies. And there was some more debate on the topic here, including some interesting stuff I’d read on why USB cables can sound different.
I’ve read a lot of good things about the Supra, which seems to be the internet-recommended “affordable audiophile” USB cable. I bought my much more expensive Black Cat cable because it was 90 ohms, and had separately shielded data and power wires, and had I known about the Supra at the time, I would have tried that first.
The test is interesting, but he’s too focused on bits and error correction.
There is no error correction on USB audio, it uses isochronous transfer, it has a CRC, but the DAC has no way to rerequest the data. This is documented in the standards document, so it really isn’t open for debate.
I’d also be surprised if a significant number of bits were flipped on the wire, I’ve never put an analyser on a USB wire, but I have measured corrected errors on a network cable, and they are stunningly infrequent.
So then the question becomes what’s the difference, If I had to guess, I suspect it’s largely about noise introduced to the DAC’s power lines through the USB cable ground or 5V lines. DAC’s go to a lot of effort to galvanically isolate the USB subsystems from the rest of the DAC, and I suspect they do that for a reason, and that isolation likely is not perfect.
If I can hear the difference between power cables, or wall warts, all bets are off on how little noise on a power line can influence the output stage of a DAC or an amplifier.
I read an article on USB audio (I can probably dig it up if anyone’s interested) that said that the designers of the spec calculated that the probability of an error if everything was in spec was about one bad bit in a month of continuous audio streaming. And IIRC that was the original USB Audio spec, with subsequent versions probably improving on this.
Personally I think USB Audio errors are a red herring. Jitter, however, is a real and measurable issue. Whether it is audible is another question.
Watched this some time last week on cables in general. Thomas makes a good point reminding us that measurements aren’t science but only one part of it. I liked his take on it so I thought I’d share it here…
