I'm still not 100% convinced that Sony did this on purpose. If that were the case, it would be logical that also NW-HD3 and NW-HD5 had cripled MP3 playback, but they don't. This could also be a bug in the firmware, e.g., the roll-of is meant for low-bit rate MP3's but the code is missing the check for the bit-rate and erronously applies filtering to all MP3s. But I guess we won't know for sure before the next generation of HiMD's come out (if its still there, it's on purpose for sure). By the way, has anyone tried this on any other 2nd gen devices besides the RH10? If the filtering is done on purpose, there might be a similar setting as for the Euro output power limiting that could be switched on and of in the maintenance mode.