What is the best digital source

[Jean-Marie]

I have tested the following configurations:

1) Macbook -> WiFi -> Airport using Apple Airplay -> SPDIF -> Devialet
2) Macbook -> WiFi -> Airport -> WiFi -> Devialet using Air
3) Macbook -> WiFi -> Airport -> Powerline (Eth over power) -> an other Airport using Apple Airplay -> SPDIF -> Devialet
4) Macbook -> Ethernet -> Devialet using Air
5) Macbook -> WiFi -> Airport -> Powerline -> an other Airport creating a 1m long dedicated WiFi Exclusively for the Devialet -> WiFi -> Devialet using Air
6) Macbook -> WiFi -> Airport -> Powerline -> Ethernet -> Devialet using Air

configurations 1) and 3) were sounding identical between each other but were having a spatial resolution and stability slightly inferior to 2), 4), 5) and 6)

2), 4), 5) and 6) were undisguishable to my ear and therefore I settled on 6).

I should probably mention that I'm using iTunes as my player and I'm using probably 98% of 44.1KHz 16 bits ALAC either ripped from my CDs or bought from Qobuz and 2% of 'High Res' files.

Also to mention that the difference of spatialization was perceptible mostly on classical music played by large symphonic orchestras and much less on smaller formations or Jazz or Variety.