Hi. I'm new here. I've been lurking for a month and never registered. But for some reason your thread convinced me to! I think it's because I had a similar experience.
I went on an anime music kick one time, and had the K-On opening and ending song because I thought they were great the first time I heard them (and they ended up being the highlight of the show, in the end). This was with my old headphones. They sounded great.
Then I got my current Grado SR60i and fixed my bad habit of listening with X-Fi's surround sound stuff, and I now find them unlistenable, the ending in particular. Tons of clipping, perfectly even loudness with no dynamic, the worst victim of the Loudness War that I've heard. That's when I kind of cursed my newfound interest in audiophilism, then promptly deleted the files.
Your thread (and the fact that your songs are K-On-related specifically) got me interested in looking up exactly HOW clipped and loud they were. So I downloaded a temporary copy of the ending song real quick and threw it into Audacity along with another J-Rock song (Rolling Star by Yui. If you like J-Rock look her up. Seriously). Then for comparison I tossed in one of the songs from one of the jazz CDs I picked up in a garage sale last weekend, expecting it to be as well-mastered as to be expected. Here's what I got:
So, to answer your question of whether or not all J-Rock sucks, or if it's just the production geniuses behind K-On, the answer is:
BOTH!
Seems like the Japanese producers of modern music are just as obsessed, or even more so, with the Loudness War than American producers. Looking at the Yui song, you get the loudest dB possible and a relatively even sound, although there are some dynamics in certain parts. I don't think it clips much, though, as it sounds okay to me. With the K-On song you get a total brickwall of sound, the worst I've seen in Audacity (although I don't have Metallica's Death Magnetic to compare it to
). And when you listen to it, there's noticeable clipping and lots of mess caused by complex instrumentation all leveled off at the same volume. It almost LOOKS painful, let alone SOUNDS so. I can't imagine the rest of the K-On songs are leaps and bounds better, plus (this being totally my opinion) I can't imagine a lot of effort goes into a Character CD song at any stage of production. Then there's the jazz piece, which is far below the 100dB mark, and both looks and sounds dynamic as jazz and classical should.
And as much as I love The Pillows Scott_Tarlow (which is a lot, as they're one of my favorite bands), they're no better. I don't have a picture of it, but I threw their song Instant Music into Audacity and was met with a wall the likes of K-On. Only it doesn't sound like it when played because it probably evades clipping every other note. I've found after getting the SR60i that Pillows songs have what sounds like a thick haze over them, like they're muted, which is a lot like how K-On sounded. Probably the mushy blending of instruments all set to the same volume? Still good music though.
Now to go post somewhere else maybe?