AAC- was good quality but lacked sharpness as well as sharpness. MPEG-GOOD- was loud intense and sharp but not as good as the AAC file. MPEG-HIGH- was not sharp but intense and flowy. MPEG-HIGHER- you can really hear the instruments and it flows really well. Youtube- worst quality and very soft. AIFF- Best quality and the greatest sound. 1)AAC- Advance Audio Coding, standard, lossy compression. MP3- is a coding forming lossy data. AIFF- is the best form of audio data. 2)