Ok quick background my lcd3 are from the original batch oct. 2011, RMAed in april of 2012 and I bought them a year ago right around this time from the f/s forum.
No problem at all for a year, until i changed my worn out leather pads with some new ones. The new pads created much more suction/pressure than the old pads and i found within a few days the right driver would intermittently cut in and out if i adjusted the hp's placement on my head. It seemed like the pressure was causing the driver to exceed its 2.5mm excursion limit, it would cut off then quickly move to normal. However every once in awhile the pads would compress and driver would cut off and stay off, untill i tapped lightly on the grill.
So i contacted Audeze who like many have commented on here before, were on top of things. Very prompt replying back, sent them across the country and had them fixed and back in less than a week, pretty painless and its comforting to an Audeze owner to see how the well the business stands behind its product.
Top graph is the April 2012 RMA (veil check). Bottom is the June 2013(driver fix) freq graph. Alright im driving home from the post office and am getting nervous about that dip to 8k in the new graph. Now I dont know if they changed out the drivers or fixed the current ones in there but the headphones sound nearly identical as they did before. I listened to this pair of lcd3s on almost a daily basis for a year, i feel pretty familiar with my reference tracks, that I can say that with relative certainty. Which doesnt bother me a bit they sounded phenomenal before and still do, kinda glad nothing did change.
Also for the record im not a big believer in Audeze having a burn in period. From my experience buying a new lcd2 and the lcd3 (had est.20hrs), i cant notice any significant changes in the sound over time, they sound pretty consistent but that's imo, ymmv, blah blah. if something changes drastically in the next 150hrs i will definitely report back.
Also here are some pics of my lcd3