Everyone has differences in their systems and not surprisingly have differing results. I try to normalize my streaming results by comparing it to my other sources. I have four different sources now: Vinyl, CD, FLAC files stored on my music server and Qobuz. I'll stay away from vinyl for now. So on the digital side I am using a CD transport and separate DAC. Then I have a music server with USB to the DAC. I ripped my CD collection into FLAC files stored on my music server. After trying a couple of different USB cables I'd say that my CD to FLAC files are very close in sound to playing my CD's directly. I did some back and forth but mostly I like to listen to a song and then play it again from the other source. I am satisfied that to me the music server and CD transport are very nearly the same. I use ROON but do not use any oversampling or conversion. I have ROON set as basically a pass through with PCM output to my DAC. I tried DSD output with various filters but never sounded as good as direct PCM out.
When I started streaming I was using an ethernet cable from my router directly to the music streamer. Streaming 16/44 was clearly less than CD quality. Then I added a cheap network switch and heard some improvement. Next, I tried FMC's and found fiber was a good upgrade in the sound. The differences between streaming 16/44 and CD was getting smaller. I took out the cheap network switch and found that was an improvement. Next added the Finisar 1475 SMP's (these are the plug-ins found on the FMC boxes) and got a nice improvement. At this point 16/44 streaming was very close to CD and hi-res FLAC files vs streaming hi-res was also very close. Finally, I added the LHY SW-8 network switch after the Fiber and changed to Pangea ethernet cables. I hear no difference now between spinning CDs, FLAC or streaming.
