Franco, if you’re very sure that you’re listening to exactly the same source release material, both your CD and whatever Roon is streaming (I assume it’s your own ripped CD), then no, the volumes should not be different.
The other thing to check is that you haven’t turned on “Volume Levelling” on Roon, make sure thats off; https://help.roonlabs.com/portal/en/kb/articles/volume-leveling
@Anupc, no it’s a general observation that is not based on specific cds or files. I’ve noted that when listening to cds I can set the volume much higher. The Bartok is set at 6 db and volume leveling on Roon is off.
I’m sorry, I don’t quite follow what you mean. With CDs, you can increase the Bartok’s Volume higher, but with Roon you can’t? Because? 
@Anupc, I mean that the volume that I listen to CDs is too loud when I play music from the Bartok. I use the Bartok as a source only and my preamp is an Audio Research (Ref 3).
I’m sorry Franco, I still don’t quite understand 
Earlier you said when you play CDs you can “set the volume much higher”, but now you’re saying when you play CDs it’s too loud. So which is it?
Can you describe it more explicitly? It would help if you don’t generalise.
Give us an example of a specific CD where when you listened via the Accuphase Transport into SPDIF on the Bartok, it’s loud. But that same CD ripped and played via Roon on the Bartok with every setting remaining the same, its not loud?
Apologies for the confusion. As I said, I have not done any direct or specific comparisons yet but the volume at which I play CDs (via the Accuphase Transport into SPDIF on the Bartok) is substantially higher than the volume at which I play the same music out of Roon streamed from the Bartok. Does that make sense?
Just read a Bartok review, the tester (stereoplay) said that streaming has the edge vs. the other inputs…if that helps:-)
Its not just volume levelling that needs to be off, but also device volume needs to be set to fixed. Is yours set to fixed?
Fixed Volume might be a good advise, but for dCS is not necessary [Roon default setting for dCS is Device Volume] , unless you have volume problems. Please note the difference:
Use Device Controls [Device Volume]: causes Roon to pass volume commands on to your device via the device’s driver.
Fixed Volume: Use this setting if you plan to control volume elsewhere–for instance, on your preamplifier or AV receiver. It’s there to solve problems–if you don’t have problems, you don’t need it! Generally, the problems this solves are phrased like “I’m not getting full-volume output even though I have Roon set to Fixed Volume mode or the Software Volume slider is at the maximum”, or sometimes “I’m not getting bit-perfect playback, even though I’m in Fixed Volume Mode”.
https://help.roonlabs.com/portal/en/kb/articles/audio-setup-basics
Thanks guys I’ve now set the volume to fixed. Let’s see what happens.
Just add that JRiver software in my PC works really well streaming UPnP my ripped CD , very good SQ and easy to use ( via Mosaic)
I’ve always found it odd the way that the Roon instructions phrase this. I realize that many Roon users might not be fully conversant in audiophilia, but the reality is that “Fixed Volume” is not merely for solving problems, as Roon’s own words illustrate. It’s there as a tool if you need or want Roon not to change the DAC’s volume. In my speaker and main headphone system, I don’t use my DAC as my volume control. Simple. So I set Roon to Fixed Volume. But at my desktop, where I have the Matrix, I’ve set Roon to allow volume control for convenience. Choices, not problems. 
I agree with you, Greg, Roon phrases it odd. They offer choices, but choices for many people actually cause problems. Maybe therefore they want to limit choices, and tell users only to set Fixed Volume (i.e. to change their previous/ default setting) in case of an already existing problem. Once you have set Fixed Volume, and forget about it, and later need Roon to change your volume, it will not work. Problems!
Here is more to it, to make it complicated (but interesting!):
Probably correct. I think it’s true that Roon has a pretty simple layer of use and admin, but with lots of depth and choices. Yes, people will forget, but it’s so easy to change in ten seconds. But you’re right, people will forget. Heck, I sometimes fail to pay attention to which DAC I am trying to control! And it’s painfully clear that many people are clueless about the equipment they own.
