This. Maybe people have different hearing skills also. But I can definitely hear the artifacts in MP3s, like hihats getting muffled and the deep base getting lo

This. Maybe people have different hearing skills also. But I can definitely hear the artifacts in MP3s, like hihats getting muffled and the deep base getting lost in the sea of MP3 compression. With good headphones (I'm talking 200+ euros class headphones for example) there is a certain difference between even a 320 kpbs MP3 vs a 128 AAC. AAC or OGG for example just has better usualy clarity in the sound, the bass is clearer and more distinct and the hihats and other hi sounds aren't muffled in the background or don't lose their clarity like they do with MP3s. And like the parent wrote, once you have heard those 'signature losses' of the mp3 codec, it's very hard not to notice them.