For a while there has been a push for high quality music files and so Apple's project was greeted with unanimous cheering from those who were happy to pay more cash to get music quality which could be played on a decent stereo.
The music industry was also interested because it resembled, to them, an alternative way of killing off pirated low resolution files. But according to CE Pro, Apple's approach to high res music stinks.
Bobby Owsinski, a LA based recording engineer had a look at what Apple was doing to create its Mastered for iTunes range and discovered that it wasn't much good. This is mostly because Apple's own software, Sound Check in iTunes, made things less useful.
The British mastering engineer, Ian Shepherd, looked even deeper using a music engineering tool called a null test. This involved reversing the phase of a song's waveform so that after a song's waveforms and volumes are matched in software a mixing engineer can play them back to see if the song's out of phase waveform cancels or nulls out the normal version of the song.
According to CE Pro, Shepherd said there was a sonic difference between the Mastered for iTunes waveform and the CD waveform. This means that Apple's Mastered for iTunes isn't 'closer to the CD' than a standard AAC file from Apple's iTunes store, as Apple claims.
He said that there is some slight-of-hand pulled with Apple's method because optimising lossy codecs shouldn't be necessary. In other words, the company is not producing anything like CD quality and Mastered for iTunes is nothing more than marketing hype.