I was wondering if there's much of a difference in audible quality between these 2 formats. I have some old mp3 files that are 128 kbps, and I have purchased a few songs off the iTunes store and see that they're encoded at 256kbps AAC. I listen to my music mostly on my iPhone using the built in speaker and the earpods, and also on my iMac, MacBook as well. Also have a few bluetooth speakers around the house that I stream to. I am considering repurchasing my music on iTunes if it makes a big difference.