Have an iTunes library full of uncompressed audio? Then you’re probably familiar with iTunes’ built-in option to automatically convert higher bit rate songs to a lower bit rate—and thus smaller file size—when filling up an iDevice. Previously, this option was not so audiophile friendly, due to its 128 kbps restriction, but with iTunes 10.6, you have some freedom to lower the file size of AIFF and Apple Lossless files while…