Maybe it is just me, but I think the AD700 sounds colored. Low end does not seem to have much detail or presence in most of my music too
Not as if its a bad thing, because I find it suits the signature well.
I ordered the K550 over the weekend. Care to give a comparison of both? The suspense is killing me now
If I compare these headphones with their sound when they are on flat with no bass boost on a good recording, it is noticeable that the K550s have quite a bit more impact to the bass but it still is for sure not a bass heavy pair of headphones. There is quite a big difference in their soundstage. The AD700s feel more like their sound surrounds your ears more than the K550s and they give a more spacious sound. This could be to do with the fact that they are open-back or that they have a slightly bigger and angled driver. If you are after more bass, the K550s don't work quite as well with bass boost as my AD700s because they are closed back and they already have more anyway. If I compare the treble on the two, I think the AD700s are much much better here. I have always loved their very bright sound. The K550 also has a lot of treble but it doesn't sound like it is quite as transparent sounding like the AD700s are. I believe this will just be the differences between open and closed.
Where the K550s are better than the AD700s is their build quality which you should expect since they cost more. They feel very very solid compared to my AD700s. They are also much better because they don't leak sound anything like the AD700s do. They are much more easy to carry around too because they fold flat.
I still think that the AD700s are overall better value for money for what I paid because I think that apart form the bass, they do sound better than the K550s. Their soundstage is quite a bit better.
I am still really pleased that I got the K550s though because they are better in the areas in which I expected them to be which is the bass, build quality and portability. They are also a huge amount better and blocking the sound from around you. You would expect that with closed-back headphones though.
Hope this comparison helps.