With EMI offering higher quality music files for a small extra cost, you have to wonder whether it's worth it. Can you, in fact, tell the difference?
PC World has produced a page with a quick challenge. Eric Dahl has posted very short clips of Mozart and R.E.M.'s Man on the Moon in both 128kbps and 256kbps AAC so you can have a listen. Unfortunately he hasn't included WAV files as well, but you can easily produce your own test files -- and have the advantage of choosing music you know well.
And if you really want to know if you can actually tell the difference, you'll need to set up a double-blind test.
The drawback with PC World's test, of course, is that it isn't just testing the audio files, it is also testing your PC and speakers/headphones. You are also testing your knowledge and experience.
With the average PC set-up, or a typical portable music player, I reckon most people would find it hard to tell the difference in a double-blind test. Playing the same files through a good quality hi-fi should make the differences more obvious, possibly very obvious.
Of course, the fact that most people can't hear a difference doesn't mean there isn't one. Lossy audio compression frequently produces digital artifacts that are not as obvious as, for example, the visual blockiness you often get with digital TV displays, but they are there. If someone tells you what to listen for, you can probably learn to spot them -- but why would you want to?
However, there are other arguments for going for the 256kbps files. One is that they come without DRM, so you have a much better chance of being able to play the same files in the far future. Another is that even if you can't hear the difference now, one day you may be able to -- either your ears may become more attuned to digital artifacts, or you may have a better-quality reproduction system.
At the moment, I suspect only a small proportion of the population has heard the musical quality that can be extracted from a CD or, better, an SACD. But once you've become used to a system that distinguishes clearly between different instruments and separates them clearly in a 3D sound stage, then you tend to notice when, for example, DAB radio turns them back into mush.
And if more people's ears are educated by hearing better quality sound from Blu-ray and HD DVD discs, then at least a few may become more sensitive to the audio quality of file downloads.
