As a matter of interest who here specifically notices the distortion that the SRH1440 has with frequencies below 100hz? I can't speak for the 1840 but I actually had my pair shipped for testing under warranty just on the off-chance that there was something wrong. Apparently several techs tested with sine-waves and couldn't hear anything strange. I even brought a 50hz sine clip on my mp3 player into the store I purchased the 1440's from (a local instrument and music shop), it was the weirdest thing when three different staff members couldn't hear what was clearly obvious distortion to my ears. I even tried A ->B testing between my old AD700's and the shures "So can you hear that these headphones have a less distorted sine wave especially in the right ear?" "Sorry it sounds the same to me."
Ok so I am only 25 and I've always made an effort to look after my hearing but all the same I expected at least someone to notice this distortion too. Not that I'm really complaining as this effect is only noticeable in a small percentage of what I listen to, tracks with hard hitting pure bass that is separate from other frequencies in the mix certain trance and dubstep tracks mostly. All the same, it was an eyeopener for me that people could not 'hear' a certain details that were just so obvious to me especially when these people clearly played and had an appreciation for music themselves.