I thought that at first - but it's simply a matter of getting used to it's particular sound sig. It's brighter than the HD600 for sure, but less so than the Beyer DT880.
From my experience - it's one of those cans you need to spend some time with before making a decision on it. It grows on you. I also thought it was quite bass light at first listen. After a while you realise how good the bass really is - linear, extending reasonably well, no mid-bass hump, but no 'holes' either (like the SRH940).
It's the imaging and separation that get me though - a really accurate sound stage.
I read (before I got them) that they are like a poor mans HD800. I have no idea if it's true or not - but I do know that if they have some similarities - then some time in the future I will need to buy an HD800. In the meantime, I really like these. So much so that I'll even be selling my DT880 soon - and I love those cans. I just never use them anymore.
Since the SRH1840 arrived, I've sold my K701, Q701, HD600 - and soon my DT880. That'll give you an idea of how much I like the 1840.
Can't believe you have betrayed our MidFi madness. That said I have upgraded my source and amp from a NFB5/DV336 to a NFB10/LF339 XDD