Back in the day when everything audio was analog, we all understood what was noise. We had hiss from the electronics, hiss from the tape decks, hiss, hum and crackles from records and phono cartridges and even an AM radio station could sometimes bleed through to the speakers. Digital noise manifests itself differently. I see these "tech" guys on the internet showing FFT plots of Signal to Noise of a DAC and judging this cheap DAC better than that expensive DAC because the noise plot looks better. But what are they really showing? Is it the FFT plot of the digital signal or the analog signal that they are showing? If it is a post DAC analog signal then the question is how good is good? CD players have been claiming 110dB-120dB S/N since the early 1980's. In the end, these "tech" guys are merely reciting technobabble. No relationship to the sound. Pretty graphs impress people. I watched execs fall for the pretty graphs in the business world for years.
If anyone here on these forums worked along side Al Gore to invent the internet, wrote the IEEE specs for internet gear and/or designs and builds internet gear raise your hand. You might have some wisdom regarding these topics but even design engineers don't always fully understand their products once they go out into the world and are applied in ways they never considered. (Consider the Fast and Furious movies. I know full well that GM never tested a Pontiac Fiero in outer space.)
The bulk of us on these forums are Application Specialists (mostly self trained) of Audio Systems. We have varying levels of understanding of acoustics and electronics. Some of us might even be able to do the math up to some level. So I don't understand why so many here have to try to explain or convince others how digital works or doesn't work or why cables work/don't work, etc.
Back to digital noise. I don't hear noise with digital in the form of background hiss or hum. What I hear as I added fiber optics and then a high quality network switch, LPS's and better ethernet cables was 1) Smoother highs, 2) better bass, 3) improved clarity, 4) Better, more focused imaging and 5) bigger soundstage. I can listen to streaming all day. It sounds that good. I have a great vinyl rig. I play records and love the sound. I play CDs and love the sound. I can stream and love the sound. It is a great time to have a stereo, I think. Streaming or local 96/24 files seem to sound the best. It rivals the soundstage of vinyl. So here is a puzzle- if vinyl has such a low S/N compared to digital, why is the soundstage and detail of records so good? (That's a rhetorical question. Please- no technobabble about why vinyl sounds better/worse than digital.)