For months I struggled with frequent audio dropouts while connecting to stereo through my Airport Express from my Mac laptop. My connection was strong (5/5 bars on wifi) but I still had dropouts. I tried every manner of fix and none was satisfactory. Until now. I seem to have stumbled on a solution and its one I had not read about before. No doubt it won’t work for everyone because of the many different possible causes for bad connectivity to your AirTunes device of choice. But here’s what worked for me.
I was able to dramatically reduce the frequency of dropouts playing music through iTunes by enabling the separate 5ghz network option in my Airport Extreme and then connecting my Mac to that new, 5ghz only, network rather than the 2.4ghz network. After that smooth sailing!! I have a central Airport Extreme to which both my Mac and my Airport Express (which connects to my stereo) are connected. Using OSX Lion’s built in wifi troubleshooting app, I noticed that when I’m not right next to my Airport Extreme, my Mac often switches to the 2.4ghz network. I live in an apartment complex and I can see lots of wifi networks nearby operating at 2.4ghz. So my theory is that by forcing my computer to use the 5ghz signal (since its just as strong where I use my Mac) I’m able to avoid the congestion on 2.4ghz. Let me know if that helps you out and good luck!