iTunes cuts out while playing

Playing mp3 files on my Mac, iTunes will be stable for hours, but if I move a certain distance outside, iTunes cuts out. I thought this might be because my Mac was trying to find WiFi. However, I turned off WiFi, and it still does the same thing. Does iTunes have a hidden WiFi connection?

I have read several threads of iTunes doing this with AirExpress, but I am not streaming or using Air Express or Extreme.

Most signal problems are down to buffing. You said even if the wifi is turned off this happens. Do you have any other software playing at the sametime that hogs or need the cpu to update. Try using the monitor software app in utilities to see if there an over use on the cpu and ram chips.

When you say "playing MP3s on my Mac," what do you mean exactly? Are you playing MP3 files that are locally stored on your hard drive? Or do you mean you are streaming music from some other source, which is of course dependent on Wi-Fi (regardless of whether you are using an Airport-based router or not)?