It's not the digital wireless transmission most likely unless perhaps you have a bandwidth limit set on squeezeserver (not the defaultqhich does not set a limit). This might be done to avoid rebuffers that might occur if your wireless network were a bottleneck. That would only likely occur though if you had multiple squeeze devices streaming concurrently or others were using wireless bandwidth for other tasks concurrently, and/or if there is a weak signal between either server or sb and router.
Realize that the job of any network with a music server is merely to transfer bits fast enough to keep up with real time play of music. Data transmission itself across any network, wireless or otherwise, has absolutely nothing inherent to do with sound quality, which is 100% determined by the combined process from the player (sb) to dac to amp to speakers. So the problem is most likely there somewhere, assuming aso that you are getting accurate rips to disk. What CD ripping software are you using? Make sure also that nothing unexpected is happening there. Some ripping software is designed to enable faster rips by reducing rip quality using error correction techniques that might adversely affect sound quality.
Realize that the job of any network with a music server is merely to transfer bits fast enough to keep up with real time play of music. Data transmission itself across any network, wireless or otherwise, has absolutely nothing inherent to do with sound quality, which is 100% determined by the combined process from the player (sb) to dac to amp to speakers. So the problem is most likely there somewhere, assuming aso that you are getting accurate rips to disk. What CD ripping software are you using? Make sure also that nothing unexpected is happening there. Some ripping software is designed to enable faster rips by reducing rip quality using error correction techniques that might adversely affect sound quality.