SQ Comparison of 3 streamers

And btw, handing off the file unchanged doesn’t mean every streamer doing bit perfect transfers sounds the same.  That’s the whole point of this thread.  There are the various noise components (jitter, electrical, rfi/emi, etc.) that the OP and I have been discussing that can account for sonic differences, depending on your dac.

@mdalton 

For those of us who are not computer geeks, this just means someone gives you a file, you don’t open it, do any redactions (joking) or changes, and you hand it off untouched to the DAC.

There is no data interface in this world that identifies the contents of the feed without opening, validating and making sure the contents are what they’re supposed to be. This includes compression and encryption/decryption.
Nothing can be done without processing the data. Or you think Roon only opens the file when DSP is engaged? How does it know what format the stream for your DAC should be passed in? Example - native DSD vs. DoP from local library. It communicates with the streamer and formats the data accordingly  

@mdalton So, with no DSP, volume set to fixed, no ReplayGain, and no fade in/out (only WiiM has it, but I turn it off), there’s nothing that should prevent us from claiming that the Volumio app or others are bit-perfect. Yet, the native apps still sound different from Qobuz Connect. I haven’t reached out to Volumio or any vendor, but I did contact Qobuz but no response. Rivo+ owners raised the same question in the forum but received no answers either, so I didn’t bother following up.

Well, that is when I seek help from AI which provide me the followings:

Many people report: Qobuz Connect > Native app sound. Possible reasons:

• More direct streaming path

• Different buffer size

• Less intermediate processing

• Different thread scheduling

• Lower CPU overhead

Seemingly sensible — but then how do you explain the opposite case with Volumio? I asked AI again, but this time I’m not convinced by its response, though it hinted at the MPD (Music Player Daemon), the open-source audio playback software used by Volumio. In short, MPD to Volumio is like RAAT to Roon — a core playback engine. Other vendors do not use MPD. The theory is that Volumio’s Linux-based software gives better control over buffering, threading, network flow, and related processes. I don’t know for sure, and right now I feel like AI is just giving me BS. Someone with audio software development expertise, please step in and shed some light on this.

I have seen tests of the actual downloaded files, i.e., where you subtract the contents of the source file from the transferred file to determine whether there are any differences in those files.  With bit perfect, this operation will sum to 0.  I think you’re just not comfortable with the technology.  That’s ok, but you might want to do a little more research if you want to understand this more fully.  Maybe a course at a local community college?  If you’re retired, like me, it’s a great way to learn new stuff.  (I took a ton of advanced math in college, like multivariate calculus, differential equations, etc., but never took any physics, even in high school; I’m thinking of picking that up at my local community college this year for kicks.). In another lifetime - 40 years ago! - I programmed early computers that ran nuclear power plants and electrical power plants.  Scary for those who know me, but still, pretty helpful for understanding some of the basics.

@lanx0003 

Yes, it is a conundrum, but there cannot be repeatable differences that aren’t explained by the programming involved, whatever it is (or isn’t), and that means it is advertent by a manufacturer.  And if a manufacturer is doing something different that sounds better, they would obviously want to market that.  I would also like to hear from folks with expertise in this area; honestly, those who know this stuff way better than me tend to be a bit skeptical, and the next thing you know, you’re hearing from Amir that you’re gonna have to submit to a double blind, lol!  Of course, the truly skeptical among us would start to suspect Volumio is sabotaging Qobuz Connect to get you into their ecosystem.  But I’ve no idea myself.