Hey guys! So I have a great story to share regarding my beloved DT770 Premium 600 ohms. Like a complete and utter idiot I took a vacuum cleaner hose to the right driver/cup. :( That's right. Obviously I know using a vacuum on a driver is really, really stupid but somehow I had a brain fart. I was trying to get all the hairs out of the right side pad & cup and the vacuum was sitting there so I tried it. As soon as I put the tube of the vacuum against the pad covering the driver I knew I was making a huge mistake. Sure enough, when I put the 770s back on, the right channel was barely making any sound and when it did it was crackling like mad. Boy it sounded terrible. 'There goes $250 and a great pair of headphones that are discontinued...' I thought. I set them down and went to go let my dog back inside (his endless shedding being the hair problem that started this all). When I came back upstairs and put the 770s back on I was shocked to hear them now have full sound in the right channel but it was still crackling quite bad. So I fired up some 30hz and 50hz test tones (from this site) and sure enough volume was now perfectly balanced between the channels but there was still crackling in the right side. I was absolutely blown away while I sat there listening to monotonous test tones and hearing what sounded like the 770 slowly unwrinkling its own driver cone. The rattles and crackles got faster and duller until, just a couple of minutes later, they were gone. I was absolutely stunned, I must say. The sound was 100% back to normal. I've been listening to these all day today and yesterday and they are indeed 'fixed'. Somehow my completely idiotic move that should have destroyed these headphones was magically undone by the headphones themselves. Phewwwww. I will never get a vacuum cleaner hose anywhere near my drivers ever again. All I can think is that Beyer obviously used some good materials in these drivers that allowed them to go completely inside out, for the most part, and then work themselves back to the right position without tearing or ruining the sound quality. Amazing.
That's the power of German engineering (or dumb luck!)