Apple’s iTunes Plus is here, featuring higher-res files and no DRM. CDM reader Ryan Pollack points us to Slashdot, where readers are abuzz about a Maximum PC taste test shootout:

“Maximum PC did double-blind testing with ten listeners in order to determine whether or not normal people could discern the quality difference between the new 256kbps iTunes Plus files and the old, DRM-laden 128kbps tracks.

But wait, there’s more! To add an extra twist, they also tested Apple’s default iPod earbuds vs. an expensive pair of Shure buds to see how much of an impact earbud quality had on the detection rate.”

The result is, not surprisingly, better headphones are better than poorer headphones, more bits are better than fewer, and both is better than one or the other, but bits are more noticeable if the headphones are worse. If you want to spoil the results of the Maximum PC shootout, read that sentence nine or ten times until it makes sense.

Apple Takes a Bite out of DRM [256 kbps versus 128 kbps bitrate, at Maximum PC]

So, who here has given the iTunes Plus store a try? (Old news to many of you; see our previous stories, As Other Music, Others Embrace Downloads, is Big, DRM-Laden Online Music Out? and Where Do You Get Your DRM-Free Music?)

I expect you are truly discerning listeners, of course. Get someone to help you with the blindfold. Slapping your forehead against an Apple Cinema Display hurts bad.

Talk to everyone from armchair music production critics to dyed-in-the-wool pro engineers, and you’re likely to hear about how today’s records are over-compressed. (We think this is what Bob Dylan meant when he said records “have sound all over them.” But we made fun of him anyway.)

To audio lay people, though, it may be tough to describe exactly what this means. One music fan has taken the battle to YouTube, with a graphical and aural demonstration of exactly what the technique (technically “brick wall limiting”) does to the sound. Rather than approach this the traditional way, he takes a nice, clean 80s track and imagines what it might sound like in 2007. It’s actually not an implausible result:

(thanks to Matrix of Matrixsynth fame)