Hi Wertigo,
First I have to say I find this headphone much more difficult to assess than others, to me its sound is sometimes great, sometimes weird, I still have not made up my mind completely. As for its neutrality and/or bass heaviness: Of course I could be the odd user out there and I have no problems in accepting that title
. But if you look at other reviews on this forum or on youtube, I would say that there is a consensus building: That while these might be great listening cans, they are probably not the most neutral and objective headphones. In spite of what the Neumann brand image implies. Quite a few people say that while its bass is of great quality, tonally, it can be a bit overpowering.
Of course all of this is subjective and if you're a basshead, these might be right down your alley. I myself like deep and dry planar-like bass. And to give the NDH 20 some credit, I think it has a lot of those qualities, in spite of having dynamic drivers. My criticism is purely aimed at the tonal balance. I would like a tad less lower frequencies and may a bit more sparkle in the higher register. Having said that, it is a headphone that reacts well to EQing. While using EQ was absolute blasphemy for me not too long ago, I do use it with the NDH 20. The real reason is that the NDH 20 is a fantastic combination of great sound and portability. So I made some concessions and apply EQ, because it it worth it to me. I enjoyed the NDH 20 on many travels.
For home use, I think there are better alternatives. Elegia, LCD 2CB, but for me the portability of the NDH 20 is the killer argument that made me keep it. Aside from the good sound quality (my earlier criticism is complaining on a high level, as the Germans say....), great build quality and ok comfort.
Just my 2c.
Oh, and while Germany might be the home of techno, the Netherlands is the cradle of EDM! I am allowed to say so, because I call both countries my home.