AES/EBU vs XLR cables for digital connection

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.

@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.

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 

Sent you a pm to help with an explanation 

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.