Not sure what you're talking about. Sounds fine to me. Maybe it's your internet connection.
Also you should probably provide information about the how you are encoding the audio & whether it matches the original encoding fo the audio before you rendered out the video for Youtube. These are the relevant factors...nobody's going to be able to listen to a song and tell you what the problem is, especially when the problem is a s subtle as it must be here considering I don't even hear it. Provide the necessary technical information...if you don't know what technical information is important when dealing with audio files then THAT might be part of the problem.
Are you still facing this problem with audio distortion? If not, let us know how you solved it. If so, please let us know so we can assist you further.