USB connection and Roon volume control.

[BoyScout]

Since you haven't had a reply, I'll say what I THINK is the problem.

You're talking about 2 different connection methods, ethernet which is a network connection and USB which isn't a network connection. The information which can get passed on each of those connections is different.

It seems you're using Roon. With ethernet the Zenmini will connect with the Devialet using either Devialet's AIR protocol or Roon's RAAT protocol. Both of those protocols allow Roon to access the Cevialet's volume control directly so when you adjust the volume in Roon you are effectively doing the same thing as using the Devialet remote and Roon will give you a volume level readout which matches the volume level shown in the Devialet's display..

When you connect via USB Roon does not have access to the Devialet's volume control. When it adjusts the volume what it does is it reduces the level of the signal being sent to the Devialet so the Devialet is no longer receiving a bit perfect stream. That's why Roon is showing a volume scale from 0 to 100 instead of the volume scale from -97.5 dB to +30 dB you get when using an ethernet connection. You cannot control the volume in the same way as you do over ethernet when you're using USB. Using USB you can send a music stream to the Devialet's DAC but you can't control functions like the Devialet's volume control which you can do with an ethernet connection.

Your best bet with USB is to turn volume control off in Roon's settings for the output and simply adjust the volume with the Devialet remote. The reason why you're running into volume problems—the volume tends to be too low—is you're currently adjusting the volume within the music stream signal using Roon and you're feeding a volume adjusted signal to the Devialet DAC and whatever volume setting the Devialet is set to is then being applied to the DAC's output lowering the volume level you hear even further.. The alternative would be to set the Devialet's volume to 0 dB and control the volume in Roon but you will never see the volume level displayed by Roon matching the level shown on the Devialet's display because those 2 volume controls are completely separate controls, not the same volume control, and you're losing any benefits of a bit perfect signal path.

Thanks David A,

Always you, ready for a hand from the other side of the planet.
Very clarifying your explanation, now a lot of details are making sense for me, still ignorant in this field of computer audio.
The sound is completely different between the two ways (AIR and Roon´s RAAT protocol VS USB), bigger and "fatter" via USB and more detailed and sharper via AIR.
I´m searching for something in the middle, i´m not sure yet if the USB is the right solution for me.
Maybe the solution is to find the right ethernet cables and leave the USB.
I would like to know which solution is the most adopted among users of similar systems, just as a starting point.
Thanks again.