Seemingly contrary to the logical explanation above regarding wireless data transfer, I have found with my SB Touch that using it hard-wired, via ethernet, does sound better than using it wireless. Sorry, I have no explanation for that, it's just what my ears are telling me. That said, I agree that bandwidth limitations are not the culprit. That would manifest itself in the form of dropouts, not a change in sound quality. I'm not sure I understand your explanation - what did you mean by "both digital outs"? The SB units only have a single SPDIF/RCA digital output. what is the other?
Logitech Duet sonds awful
I recently installed a Logitech Duet in my stereo and it sounds digital and gritty. I'm saving my cd files to WAV with Apple's Itunes and listening through the Logitech receiver with both digital outs to a Entech DAC which sounds better with my Ipod with the best resolution MP3s (highest resolution) and I'm wondering if I was naive in thinking that the digital wireless transmission wouldn't affect the sound.