Curious Evolved USB Cable Review - Can USB cables really make a difference?

A review of the Curious Evolved USB cable including the results of the Mystery Test and comparisons with the AudioQuest Diamond USB cable.

0:00 Introduction
3:46 Mystery Test results
12:31 Mystery Test conclusions
14:09 How USB cables COULD make a difference
22:22 Curious Evolved design
26:26 USB cable listening comparisons
31:20 A surprising twist
34:05 Final conclusion

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Active Speakers: Bang & Olufsen BeoLab 3 Speakers

Amps

Headphones (that I regularly use)
Closed: AudioQuest NightOwl Carbon (these may have been discontinued)

Portable

Earphones

Bluetooth Headphones / Earphones

Reviews filmed using:

[ExSkyCyclePilot]

My thoughts, hopefully taken in the amicable spirit in which they are intended...

I downloaded the first pair of files and analyzed them in Adobe Audition, and they are different. Frequency analysis and amplitude analysis show minor differences here and there, and there were visible differences in the waveforms themselves. I also downloaded files J and K. I inverted one, and mixed it with the other, and got a flat line, which proves that the files are indeed identical. Yet, half the listeners thought they could hear a difference between them. From a statistical standpoint, this shows that the margin of error in these tests is astronomically high, rendering the data virtually useless. It's interesting, but scientifically, no conclusions can be drawn from this data.

We've all seen what happens when bits get flipped or dropped with a video signal. Pixels get dropped - sometimes a few, and at other times, large areas of the picture gets blotchy. We don't see a loss of color or contrast evenly over the entire picture. The same is true with audio. If bits are getting flipped or lost, it would not affect frequency response, or amplitude, or transient response, or stereo separation evenly over time. You'd hear pops, clicks, dropouts, or other random artifacts. Just like a video signal, the signal traveling through a USB cable is digital. It is not analog, and would not react the same as an analog signal. If you took the signal from a USB cable and fed it into an amplifier, you would not get sound. This proves that the signal is not analog, not audio, and would not behave like audio.

So, the first pair of files are different. There are countless reasons why that might be. The audio is going through various analog stages on either side of the USB cables, and if you monitor an analog signal on an oscilloscope a hundred times, it will look slightly different each time. So, when that analog signal is processed by the ADC before being sent over the USB cable, the results will be slightly different every time. Send the exact same audio file through an ADC, then a USB cable, then back through a DAC, and the resulting file will be ever so slightly different than the original.

So, until someone does a double blind, very carefully controlled, rigidly scientific study on this subject, with a very large group of listeners, it's impossible to say what's going on here. What would be interesting would be to take three different USB cables, and swap them at random dozens and dozens of times, on the exact same setup, with a listener who thinks they can tell one from another, without giving that listener any feedback on how they are doing, and see how often they get it right... Let the flaming begin...

[kaisersoze]

I got my Oyaide neo d+ class B USB cable and it made a huge difference in sound quality in my audio interface and got rid of all the jitter introduced by the old usb cable that came with the audio interface thanks for putting out these videos they're very educational.

[manueljenkin]

Two simple reasons
1. Ground plane noise (any current flow creates a return current and charge build up in the ground and with fast switching ground bounces up and down and hard to filter)
2. Rf antenna effect (everything behaves as an antenna and the layout, shape, structure, shielding etc can change these).

The analog section of the amplifiers/dacs can be sensitive to these.

But before you go tweaking usb cables I'd recommend kicking off noise in the usb bus itself first. Either a signal regenerator (like a cheap doodlebug for 80$ diy to know what is being done, or ifi/uptone etc for big bucks and noticeably better noise filtering). But for me, the best one was a free tweak. Just change your music player software to one that plays from RAM and has minimal fetches (using the wider instruction sets like sse/avx etc). Every access has noise, so reducing access is a good way go bring it down. If you're on windows, I'd recommend trying Playpcmwin.

Bit errors are super rare. If there is an error, we have buffer underruns and it actually stutters (I could make it happen if I stress my pc). I have checked with a few others who have confirmed that bit errors are very rare enough. Rather it's all about the noise, from ground plane, or phy stress (if the data has non ideal noise/timing properties) the phy would be moving to a different mode hence causing more noise into the analog side.

[net_news]

I have a regular Curious cable that use with my Chord Mojo, it's very good It doesn't improve the sound signal but It removes electrical noises. It's a very good cable.

[joetori]

Love the preambles and definition of USB cable!

[gioponti]

In my experience some DACs (they are responsible for tonality, aren’t they) are influenced in their sound and tonality by things like attached cables or also power supply, also grounding, or to be more specific, ground potential differences between streamer or pc, DAC and preamp. So unless you got this sorted in the first place, the usb cable can even influence tonality, or, to be more precise, different usb cables do so in different ways.
The other influence on tonality I have noticed is AQ‘s DBS system: if you disconnect the battery, the tonality of the connected DAC might change from well lit to mid centric. Again, ymmv dependent on components, power supply etc. Or input (in the case of my dac). Definitely if AQ‘s DBS is disconnected (or actually the battery set), the sound loses its polish, and becomes rather less fine, ie getting a bit more similar to a (quite rough) stock usb cable. FYI; I have moved up from stock to AQ Forest to Coffee and have experimented with alternative DBS voltages (using other AQ DBS battery packs) including 36, 48 and std 72V. In some configs my system sounded overall better w 48V (because there was a meatier bass, vs 72V, at the expense of treble smoothness, though) combined with a Jitterbug. Interestingly, using different digital source however did not confirm or reproduce this described change in tonality, and showed only less refined sound with lower DBS voltage. So, I conclude, the described influence on tonality, is a result of other factors at play, but not necessarily introduced by the cable.
Note, all tweaks & accessories not only influence quality but more or less subtly change tonality, whether fuses, AC cables, Jitterbug, ICs or LS cables. Key is to keep it in balance, e.g. by careful integration, including mains & power supply.

[Nearest_Neighbor]

Do we even need the 5v line when going from let's say a Bluesound Node to a DAC?

[DamienRamirez]

I used to have 4 cables 1.5M which showed differences people could hear "Stock" un-shielded, "Stock" shielded, Then from here 24AWG custom made copper shielded & earthed (This one made harsh treble - Cymbals, Funny enough similar but different to the unshielded stock.), Audioquest Carbon (Similar to stock but consistently more sense of "space"/"air" between sound). There was also shorter ones for the old Dac. Now I just use the AQ carbon 1.5M because screw idiots wasting my time, get more music time now & its my personal comfortable sounding cable.

[ericharrelson]

Nice review; I appreciate the effort you put in to it.

[curlmythic]

Hi Lachlan, I bought the AudioQuest Carbon USB based on your website comparison. Just WOW

[Dr.Danger.Communication]

DACs *DO* have error checking. The error correction is not the same as other data types (where the data is resent), that is true. But the DAC have usually 10ms to 100ms of correction headroom. Differences in the signal will be processed out by the DAC.

The Swenson article you cite: 1. is a white paper that was not peer reviewed, 2. is published by people selling stuff to correct the "problem" (i.e., bias), but most importantly 3. really concludes that if your cable makes a difference, something is seriously wrong with your system (e.g., current leakage).

[andershansson]

Some additional tech info... Poor impedance match between source, cable and receiver can cause signal reflections as data is transferred at a very high speed in the USB cable. These reflections can cause time errors and jitter from the usb receiver that are decoding the signal from the cable. Depending on the usb receiver and dac design this time related distortion may well cause time/amplitude related distortion at the analog output of the dac. That's one reason why resampling after the usb receiver using a good clock can be important. To reduce the dependency of the usb cable but also to jitter from the source.

[andrepoon]

Appreciate your efforts. Your data actually is evidence that the USB makes NO difference. There is no significant difference between you control study vs you study with the expensive USB cable.

You data is fine. Your interpretation (sorry) is not right.

[williamzame]

62% of the people saying they heard a difference doesn't mean there is a difference.

[aerofart]

I mentioned it in your last USB cable test, but it bears repeating: you need to measure the results between two samples of the same cable from the same mfr. If there is no consistency between two samples of the same cable from the same mfr, then none of the results from the tests you've done hear have any practical use, because one cannot say that if you buy a brand X cable, it will consistently outperform brand Y cable, or it will behave consistently better or worse than brand X or brand Z cables.

[banginghats]

I wonder if an iFi iSilencer+ and a Supra USB cable combination might be a more cost effective way to connect a computer to a dac?

[geucamole]

USB cables, or cables in general make huge difference to overall listening experience. It might not be a day and night difference and it might not mean that expensive cables are better, but I for sure can tell the difference in blind tests between cables. One example is that, with certain headphone a simple USB 2.0 cable that came with another standard PC equipment sounded actually better than an audiophile USB 2.0 cable that costs around 60 USD with LCD-X headphones, however in the same setup with Meze Empyrean the audiophile USB 2.0 cable sounded better, and again I could reliably say which cable was which in blind tests. If one can't hear the differences, great for them; but it is a fact that audio signature and sometimes quality changes by simply changing interconnects, USB cables, anything in the chain really.

[brandonburr]

Appreciate all the time that went into this review. Heard good things about curious usb cables over the years as well as audioquest and particularly to the diamond. This review is important with respect to cables and how well they synergize with systems. I think an important thing to note is the conductor material used in the audioquest diamond is silver. They tend to used silver in their higher end stuff and wondered if perhaps this was a large part of what you were hearing compared to the others, which are copper. I believe the curious is copper or some variation and the lower coffee audioquest is copper as well. I could see where in a highly resolving system that diamond would be too much of a good thing if the system leaned on the cool side of neutral. Whereas the copper cables would add back that tone, space and body. Love audioquest stuff but with anything in this hobby it will come down to how well it all plays together. Usb cables have presented a bigger challenge to manufavters to design and get right as it was never designed for audio playback at high levels. It's difficult to deal with all that noise coming computers as well. Thanks for the review!

[hadleys.]

I purchased a “Silver Dragon” upgraded silver/copper USB A to USB B cable for my Chord Hugo TT2 and to connect it to my windows PC. It makes a difference just like high end digital hdmi cables do over cheap ones. It depends how much data is being transferred across them as well.

[emmaatkinson]

Interesting findings. Did you try capturing two recordings using the same cable, invert one and listen to the summed audio? Or was the inverted sound done inside Audacity? The former might have revealed jitter side-effects that wouldn't occur if inverted in Audacity.