Although were not exactly sure when it went live, Apple seems to be rolling out a “Mastered for iTunes” section on iTunes worldwide that is populated with albums “specially tuned for higher fidelity sound.” Yesterday Universal Music Group announced several new additions to the section. New albums from UMG added to Mastered for iTunes include Madonna’s “MDNA,” U2’s “Achtung Baby,” Paul McCartney’s “Kisses On The Bottom,” and other albums from Bon Jovi, John Coltrane, and classical guitarist Kaori Muraji. Apple also recently published a white paper detailing best practices for mastering music for iTunes, and released new “Apple Audio Mastering Tools”…

To go with the section, Apple recently published a PDF detailing best practices for mastering and preparing music for distribution on iTunes. The document, titled “Music as the Artist and Sound Engineer Intended,” essentially asked publishers to submit high-resolution 24-bit/96kHz files, and not original CD masters to create the 256kbps files introduced with iTunes Plus in 2007. Apple noted: “Keeping the highest quality masters available in our systems allows for full advantage of future improvements to your music.” Apple explained it would check music submitted for “Mastered for iTunes” to make sure songs “begin with a high resolution digitization of the original analog source” and “sound noticeably superior.”

Apple also recently released new “Apple Audio Mastering Tools” which now only includes the “Mastered for iTunes droplet.” The tool is a standalone, drag-and-drop OS X utility that allows you to “automate the creation of iTunes Plus format masters” and preview music using the encoding tech Apple’s uses for the iTunes library. Apple explained: