Upgrade from NAD Viso HP50?

First I'd just like to say that I really like the HP50's, but I think I would also like to own a pair of open-back headphones.

The only pair of open-back headphones that I have spent some time listening critically to are the Fidelio X2's. I liked the openness of the Fidelio X2, but found them just a little bit dark sounding.
From what I heard, I feel that an open-back design would give me more of the sound qualities that I value. I want my next pair of headphones to have an an open, spacious sound, good clarity and a some sparkle in the top. But I can not stand a thin sound, lacking body. I am looking for something in the 300-500 euro range. Is it too much to ask?

The models I am considering are the Beyerdynamic T90 and Shure 1440/1840.

Any recommendation? Has anyone had the opportunity to compare them? Would they be a step up from NAD?

/Magnus

Look here:
http://www.innerfidelity.com/content...H0IzXQfiR1o.97
detailed descriptions, measurements and all you need to know!

Hi Magnus,

You might also want to take a closer look at the following:
AKG K712 - a marked improvement over the previous model (702) and with a sound signature that should suit your requirements. You can find them at substantially discounted prices on the internet.
Sennheiser HD700: as above.
HiFiMan 400i: One of the cheapest planar headphones available and at a bargain price; great value for money, decent build quality and very comfortable too.
Audeze el8: A tad over your stated budget but certainly worth considering. Their sound quality is hard to beat. Perhaps a look at the second hand market?
Beyerdynamic T90: Owned these for a while; build quality is sublime (far better than any of the above), very comfortable and do most things very well. Good all-rounders but I personally found their midband to be a little on the cold/clinical/analytical side of things which is the reason I sold them. YMMV though.
Hope this helps
Best
-j.

Thanks for the suggestions and your opinion on the T90's.
I'm bidding on a barely used pair of Beyerdynamic DT990 pro's, not what I had in mind from the outset, but the starting price was so low that I could not resist.
We'll see what happens.