Has anyone had any low-mid, upper bass resonance issues with their LCD-2s? I had a very odd experience which cropped up suddenly and I thought, therefore it might be a bad tube. I swapped out tubes and it seemed to be OK. I didn't listen much because the next day I'd committed to ship them out to my friend in CA to have a listen to them while I am on vacation since he could take his time with them, and otherwise had no way of listenign to a pair. He builds amplifiers and does a lot of sound mixing/recording as well...used to work for Magneplanar, been in the biz a long time...very good ears. He was curious to hear them because he uses headphones all the time in mixing and recording. Today I got an email that he'd received the headphones safely, in great shape, and that they sounded good except for an annoying resonance in the 500-600hz range. I asked him to clarify, but haven't heard back yet. He was going to try it with a more powerful 2watt headphone amp of his own design (I don't know what he was using as an amp for that initial observation). So that brought me back to my experience just before shipping them out which I'd forgotten til he wrote. I thought I'd solved by swapping tubes (it kind of sounded like a driver tube going bad), and with the new tubes I did not hear it again, but only listened to a few cuts before packing them up. It was like some of the frequencies had a bit of a sympathetic warble...like the mids were being distorted by the upper low range. It could still be just a bad tube - my tube tester needs calibration so I don't trust it to tell me the right story. But I thought I'd check to see if anyone had experienced anything at all that sounded like what I'm describing. I don't know for sure if what he's hearing is the same thing (it could have been a bad tube and what he's hearing could be unrelated - as I said, he hasn't clarified as of yet), but it is in the right region that he noted. Anyone have any similar experience or comments? I was listening on my WA6SEm.