AES/EBU vs XLR cables for digital connection


I did look to see if this issue was addressed in earlier discussions but couldn't find any specific information, so here's the story: I've ordered a Sonnet Hermes streamer to complement my Sonnet Morpheus DAC, and since the DAC doesn't have the I2S port (it's USB instead, though I understand I can change this if I want to), the best available connection will be via AES/EBU. I already have a pretty good XLR cable (Clarus Aqua) which I previously used for analog connection but I'm wondering if there's any advantage to using a true 110-ohm AES/EBU cable or if the standard XLR (the impedance of which I don't actually know) will work just as well. Have any of you done an A/B comparison between these two types of cable? Opinions are welcome. Thanks.

cooper52

And yet one more update: finally was able to get the laptop out of the equation by switching to a Samsung tablet. It was an immensely frustrating process, as Roon can be very tricky to set up properly, and especially difficult to figure out how to move the Roon core from one source to another. I’m now running it on my desktop computer which is far more convenient, as it’s pretty much always on. The tablet, I discovered (after tearing my hair out and swearing loudly for days on end) can’t serve as the Roon core, but does work very efficiently as a wireless controller to access Qobuz and my music library. Now everything’s working exactly as it should, sounding especially good, and making me happy. I have to acknowledge Roon’s customer forum for pointing me in the right direction, as the actual online technical information Roon offers is difficult to navigate and not as clear as it ought to be. But still, I got there finally. And BTW, with reference to my original post, still using the I2S connection. Haven’t yet compared it to AES/EBU, but will try that experiment at some point. The Hermes doesn’t even have a USB connection (!), so can’t make that comparison. One day, perhaps, I’ll see about an even higher-end streamer, but that’s not in the cards quite yet.

Well. After some poking around, and following sesignsfx’s most excellent suggestion, I finally discovered Roon’s DSP engine and the ability to adjust EQ with it. What a difference! Roon defaults to what looks like a flat frequency response, but to my ears it seems skewed towards higher frequencies. Boosting the bass a good 3 db and gradually rolling off the higher frequencies from about 2000 Hz  upwards has yielded some unexpectedly spectacular results. NOW what I’m hearing is much more like what I was hoping for. Of course I’ve only heard this through headphones so far, but I’m sure putting this through the speakers will sound as good or better.

One experiment I’ve yet to try is controlling Roon through a tablet or iPhone, neither of which I own yet, but stay tuned--this may change soon. I’ve tried using both my desktop computer and Samsung (Android) phone but neither will recognize the Hermes streamer.

Again, thanks to all (and especially designsfx) for the input and suggestions. I’ll post further progress as it occurs.

And as happens pretty often in this forum, we’ve strayed rather far off the path of my original post, so apologies for that.

@cooper52 

I’m sorry to hear that you’re still experiencing problems with your setup- trying to help you get to the bottom of it all-

1) You confirmed that you could get Qobuz to run wireless- did you take the laptop (and Roon) out of the mix when running it wirelessly? Was there any improvement?

2) When using Roon with your laptop are you using Roon’s volume control, headroom leveling or EQ at all?

3) In case I missed this how are you passing audio from your laptop to the dac- usb  or Ethernet?

My iFi Zen Stream can’t directly run Qobuz either. I’m not familiar with your streamer, but I was able to run Qobuz using the mConnect+ app so maybe that could work? Point is, you wanna get that computer out of the signal chain however you can. Even if you have to temporarily bypass Roon to get to hear Qobuz without the computer I’d highly recommend you do so. You’ll be highly rewarded with significantly better sound quality, and maybe you can find a way to employ Roon later if possible (I’m Roon ignorant so I got nuthin’ there). Anyway, hope this helps at least somewhat, and best of luck in your journey.

Just wanted to update the updates here, as I’ve been living with all this for some weeks now. To remind everybody, I’m using a Sonnet Hermes streamer and a Sonnet Morpheus DAC. The two are connected through i2s via what I think is a good ethernet cable. Streaming service is Qobuz, which I’m accessing through Roon on my Dell XPS laptop. (And yes, designsfx, it does connect wirelessly. Many thanks for your explanations and suggestions). Since last update, nothing has improved soundwise, I’m afraid. I still don’t think I’m getting anything like the quality I should be getting. Things are fine up to a certain point, but in the frequencies where voices live and higher, it’s still shrill and glassy. Also, dense musical textures get pretty muddy. This is not what I should be hearing.

I made a startling discovery about the Qobuz app on my Samsung smart TV, which is that there are only 2 choices of sound quality, MP3 or 44.1. It was actually set to MP3 (!) but since I’m upconverting everything to 24/96 with a Wyred4Sound reclocker, it ends up sounding quite good. I tried changing this setting to 44.1 quality, but then no sound came out. Go figure.

As far as I can tell, the Hermes streamer won’t allow direct access to Qobuz (or any streaming services) without going through Roon or similar platform. If there is a way to do it I’d be very grateful to learn how. The owner’s manual is pretty basic and doesn’t really cover much in the way of detail.

So this is where things are presently. Not a happy camper yet, but I hope to get there eventually. Still open to your thoughts and suggestions.

Thanks, designsfx for your suggestion, but I don't see how I can control the Hermes with my phone, as it doesn't seem to have wireless capability. Okay, I'm really new streamers, so maybe I'm missing something? It would certainly be a worthwhile comparison though, cutting out the middleman, so to speak. And, of course, it would be far more convenient to do it that way. Again, I'm very open to suggestions/instruction. 

BTW, it turns out that the Hermes doesn't have a USB port, just an ethernet input (to connect to the network), and outputs via AES/EBU, optical, coax, or ethernet I2S. They must have had their reasons for this, I guess...

@cooper52 

I know you’re using Roon but I’m wondering if you’ve compared streaming without the use of your laptop. Have you compared Qobuz through your streamer when using the app via an IPad or phone without the laptop/Ethernet connection? If you try that and here an improvement (or not) it may help narrow down your focus.

Another update: having put some time into listening with the AES/EBU cable, I thought I might experience a significant improvement if I went to the trouble of switching out the USB port in the Morpheus for an I2S module. They’re not very expensive and it’s fairly easy to make the change, which I did myself despite not being any kind of electrical expert. After wiring the Morpheus to the Hermes via ethernet cable (a very pedestrian one I had on hand), I did get some encouraging results. Bass and midrange presentation improved markedly, as did the stereo image, but the upper mids and high frequencies are still quite shrill and glassy. I really don’t know where the weak link is here. I’m using a Topping A90 headphone amp and a pair of LSA HP2 headphones. The Roon/Qobuz inerface is accessed from my Dell XPS laptop via ethernet cable.

I’m certainly open to further opinions and suggestions. Thanks.

My Dell laptop (dedicated for streaming only) was super-tricked out with all the bells & whistles. A lot of time, effort & expense went into it. I mean a lot!

When I finally compared it to a dedicated mid-priced streamer, the laptop was quickly dispatched to the closet. Not even close. The SQ from the dedicated streamer was far superior.

_ _ _ _ _

Perhaps, the routing through the TV sounds better because the optical cable is mitigating some noise. Still, not ideal.

@cooper52 

See thread attachment for comments on Volumino- maybe you’re better off where you are-

Volumino

Designsfx, thanks for your response. I did consider switching to Volumino despite the hoops you have to jump through to get the Hermes to recognize that platform, but for the moment I'm kind of stuck with Roon for the next year, as that's how my subscription is structured. Probably not the smartest decision I ever made...

@cooper52 

I’m not familiar with the Hermes as I don’t own one but in quickly scanning the specs there is mention of using “Volumino” as an alternative to allow the use of Qobuz. Maybe this will allow you to stream Qobuz via the Hermes w/o having to deal with Roon? I don’t use Roon but I’ve read posts from others stating that it does have its own issues sonic signature.

BTW- Your 110 Ohm cable will be better than using a typical balanced cable and shouldn’t take light years to show the result. 

A long overdue update: I tried the standard XLR cable (reminder: Clarus Aqua) while waiting for the AES/EBU cable to arrive and the XLR sounded, at best, okay. Once the AES/EBU cable finally got here, I hooked it up right away and noticed, perhaps, a slight improvement, but all in all, the difference was very small. It may be that I need to put lots and lots of hours on this cable before it shows its true colors, but in the grand scheme of things, I’m not very happy with how the combination of Sonnet Morpheus and Sonnet Hermes sounds. I’m streaming Qobuz through Roon from a Dell laptop, and I’m not getting anything like the clarity and composure I think I should. My point of comparison is the Qobuz app on my Samsung smart TV, which is connected via optical cable to a Wyred 4 Sound remedy reclocker which pushes everything up (or down as the case may be) to 24 bit/96Khz. I actually like that presentation far better. Don’t think this is how it should be, though, so I’m open to suggestions here. Thanks for the input so far--it’s been very helpful.

There is a fundamental difference between using a AES vs USB connection. In general, the USB puts more functions on your DAC (like reclocking) and was developed for the PC when it started being used as a streamer… before that the majority of digital connections were SP/DIF and now AES.

So, typically you have to try them depending on the quality of your DAC and streamer. Given that you are going with the same brand I suspect AES will be your best bet. I tried them both on my Aurender W20SE and Audio Research Reference CD9se and found virtually no difference and stuck with the AES.

Thanks for the input, everybody--very helpful. I have ordered what I think (hope) is a pretty good AES/EBU cable for direct comparison so I’ll see if I can tell the difference. Guess it wouldn’t hurt to try the USB connection too, though from what I have read/heard AES/EBU and particularly I2S beat it hands down, at least with these components. So my next step, probably, will be to order the I2S module. THEN we’ll see how things line up. I'll keep you posted when I've had a chance to try all this out. 

@blisshifi 

 

I wouldn't worry much about the digital source clock too much.  Usually the embedded clock in the sourrce would get extracted and stabilised, either with a PLL or some other secret sauce methods.

 

I don't think the results would be bad using a common analog XLR cable for digital AES input, but OP needs to try it to see if he/she accepts the output quality.

@xboom Just for clarification, not that many DACs will reclock an AES signal. With the AES interface, the clock from the digital source is preferred and the internal DAC clock is generally not utilized. Of course, with USB, the DAC reclocks with its own internal clock. Why some people prefer one cable interface over another is not always because of how the cable sounds, but because of the clock that is employed in the chain.

May I suggest you try the USB connection? Properly implemented asynchronous USB has the advantage of using the Dac’s clock on the streamer, I.e. the dac times the arrival of data rather than having to buffer and decode the embedded clock signal. I suggest you try USB with a good cable and Isolator.

The impedance matching is more for technical aspect of designing. The common analog XLR will still work, but may not sound as good.

 

The importance of impedance matching is to reduce signal reflections from both ends and would generate distortions & cause power loss to the signals. The DAC itself would internally reclock the data, and might not affect the sound after all.

 

Go try it. No worries, your equipment is not going to explode due to impedance mismatched of the XLR cables. HAHAHAHA~

You have received good answers but I suggest also trying the USB connection.

I have owned Cees Ruijtenberg designed Metrum products and would not necessarily say AES/EBU sounded better than USB.  I2S sounded good out of the Metrum Amber into the Pavane and Adagio DACs and it is easy to swap out the USB board for the I2s board.  You can order the I2S board directly from Sonnet for 80 euros.

Analog might work OK  I don't see ANY comparisons inquired about in the responses. Just try it 

I've chosen AES/EBU to go from DDC to Dac, as a preference over I2S.

Have ordered an Audience AU24Sx cable.

I haven't compared aes/ebu directly to an xlr interconnect but I was using the Acoustic Zen MC2, rca on one end and bnc on the other, and tried using a .5m Moon Audio Silver Dragon (xlr) in its place (between a Red Dragon S500 and Audio Alchemy DDP 1).  I prefered the Silver Dragon and have used it there since.  I also tried the 6Sons Audio Golden Eagle interconnect as a digital cable and it is even better so yeah, you can go with a simple balanced interconnect and get quite good sound.  An aes/ebu digital cable may sound better but I am satisfied with this for now.

 

@cooper52 You might get lucky using an analog interconnect (both regarding no signal dropouts and/or good sound quality) but there are reasons for using digital-specific interconnects:

First, impedance is very important in supporting the timing and clocking of transmitting packets of data from the source to the DAC. AES cables follow a 110ohm resistance to support this timing specifically. With proper timing of packet transmission and reconstruction, the digital signal will produce an analog signal that sounds completely in focus. If it is not, it is similar to a photo taken with a lens just slightly out of focus, which may be a bit "blurrier", or it may even result in added dropouts to the signal.

Second many digital cables implement grounding and shielding a little bit differently to preserve jitter from affecting the delicate signal while still aiding in the speed of the transmission of the data. This can result in less noise/fatigue vs analog cables of the same make/model.

But as mentioned, there's no risk in experimenting. Using analog cables in the digital chain shouldn't break anything.

110 is only the design parameter. The analog XLR will probably work well. No risk to try.

The only valid SQ comparison has to be done by you. Get some digital cables with return privileges and happy listening.

As an anecdote an Audio Envy analog IC was the best sounding cable for a SPDIF connection that I have tried. Before it broke.

Good luck, happy trails.

I use the Shunyata Omega AES/EBU Digital 1.5 m cable and like it very much. It connects my Aurender N20 server to my MSB DAC. I experimented using an USB vs AES/EBU cables. After testing for 2-weeks, the AES/EBU cable sounded much better.

I use the Shunyata Sigma V2 interconnect XLR cable, 1.5 meters cable to connect my DAC to my amplifier.