If you ignore the treble issue the 812 feel as well designed as they should in almost every way. I mentioned the comfort, which I feel is more important with high end headphones like this than with portable headphones. When something sounds this good you want to listen to it all night, and it’s disappointing using planar magnetic headphones where you start feeling the need to take them off before you're done. I’ve owned the HD 800 for more than 4 years now, and the comfort has always been one of the strongest features of the HD 800. It’s something you start appreciating more after owning them for so long. Making headphones that comfortable takes serious effort, and I’m glad AKG took the time to make the 812 live up to the standard set by the HD 800.
There’s something about the combination of the open spacious sound and bass impact that makes the 812 highly engaging to listen to. It sounds completely natural with genres the LCD-X and HD 800 can have problems with. The soundstage is the biggest I’ve heard outside of the HD 800, easily beating the LCD-X. The bass with the 812 rolls off earlier than the LCD-X in the very deepest bass notes, but the bass the 812 can play comes across with considerably more physical impact. Listening to orchestral recordings you get a huge open sound like the HD 800, except now with drums that hit with a force you can feel against your ear. I’ve never heard a headphone do EDM as well as the 812. The sound feels neutral and natural, but not at the cost of fun. The LCD-X obviously does a great job playing bass, but it can feel a bit detached with some tracks. Like you can hear the artist wanting you to feel the bass, but the headphone is restrained because it wants to act like a proper studio monitor. The 812 lets the bass go wild and makes you hear and feel it, but it’s not completely out of control like some mediocre closed headphone with booming bass.
I remember reading about the T1 and seeing them described as the more musical alternative to the analytical HD 800. I owned the T1 for a few years, and they never really clicked with me. Compared to the HD 800 they failed in many ways. It felt like Beyerdynamic had pushed it out fairly quickly in order to have something to compete with the HD 800. Not just visually, but functionally. The comfort wasn’t nearly as good, and the sound just wasn’t in the same league. The AKG 812 in comparison doesn’t have the same feeling of being slapped together quickly. The natural sound feels too well designed for that. You don’t get this kind of soundstage or bass by accident. It’s almost weird that they even have the treble issue at all. The combination of all the elements with the 812 is terrific. If you zoom in on specific aspects all the other high end alternatives might be a bit better in their own ways. But the way it all comes together with the 812 feels like a step forward to me. This is the kind of sound I want, with this comfort, with this build quality. It just had to have the treble issue. I guess headphone design is hard.