MPD, Minimserver, BubbleUPnP, Squeezelite, etc. All of these offer somewhat different sonic presentations.
tip if you want your digital to sound better still Tubulus Audio cables ,they beat cables much more $$ and only true I2S -Audio cable the AQ dragon audio only exception ,and the less expensive Tubulus Concentus is much better. And Ethernet cables very good ,always put your best Ethernet cable at your end point- Streamer
If the server software or the cables are delivering the digital file information to the dac in a different enough way to make the DAC sound different, then some or all of them aren’t working correctly. Or the DAC isn’t working correctly. Or none of them are working correctly. Or there’s some incompatibility. Or they’re creating different sounds on purpose through processing.
Maybe that’s the point here, most of the stuff that’s available isn’t actually working correctly, or even intended to sound transparent? I could believe that but I’d like to see some evidence beyond people just noticing they like one better than the other. Maybe some people like it better when they are not working correctly, or at least not trying to be transparent. How can we tell? It’s odd that these same cables can deliver huge amounts of software at blistering speed, and all of it seems to be 100 percent glitch free. The error correction works for other things. Why not audio?
I’ve seen people do experiments where they run a digital signal through a dac, and then back into an adc, and then back in to the dac over and over until obvious audible differences are apparent. If the server is doing that, running a loop to serve the data, retrieve it, and then run what’s been retrieved back through the server (and cables) should have an amplifying effect over time. Of course we could just check the first time through to see if any bits had changed. If they haven’t, then there’s no point in continuing the loop.