I have a 32GB IPhone and experience a "crackling" noise in the background when I play songs downloaded from ITunes. This occurs via either headphones, aux jack, or even using one of the docks that plays through an FM radio station. I have no noise problem with MP3s, or if I convert my ITunes downloaded files to MP3. I have no noise in phone calls. Anyone have any idea why I have this noise only from the ITunes downloaded files? For now I just convert my downloads to MP3, but this is time consuming. Any help is much appreciated....thanks.