Q: I just downloaded a live audio track of U2’s “Original of the Species.” Unfortunately, it is an absurd size, at 8.4 MB for 4:32 of audio. The bit rate is 256 kbps. Is there any way to change this to 128 kbps and/or make the file smaller? It is currently an MP3.
A: Absolutely, and it can all be done easily within iTunes itself. First, set your iTunes Importing preferences (found at Preferences → Advanced → Importing) to either AAC or MP3 of a lower bitrate (and thus lower file size per length of song).
Then, select the song (or multiple songs) in your iTunes library window that you’d like to convert into this format and bitrate. Finally, right click on your selection, and choose “Convert Selection to MP3” (Or “Convert Selection to AAC,” depending on your prior decision).
A copy of the song will be created in the new format, just below the original. You may now delete the previous copy from your iTunes library.