If I have a 320 bit rate song encoded in MP3, and want to "downconvert" it to 192 for space or other reasons, would I be best keeping it as MP3, since it is the same format? Or will going to AAC be better, even in that case? I know AAC has a reputation for being more "musical" when encoding from an original source. But I'm wondering if, since I would be switching from MP3 to AAC, if the sound gets "confused", and therefore is sticking with MP3 would be better. (Yes, I know "double compressing" is not something I generally want to do. Just interested in opinions regarding this fact pattern.) Thanks.