I read this thread with interest before getting a pair of NDH 20 headphones. Although I hope to write up a little more about my impressions and thoughts later, I was particularly interested in the discussion around the comment below, because it reflects one of my strong impressions of the headphones.
One thing that has changed in the 25 years I've been interested in high-fidelity audio is the kind of music that consumers of 'audiophile' oriented equipment listen to. My brother used to work in the industry, and he and many of his colleagues, and their customers, tended to listen to a lot of live acoustic music, especially jazz and to a lesser extent classical music. Of course many liked what we would have called 'classic rock' then, too, but few albums were considered audiophile material.
I notice that especially those interested in headphone audio, or at least especially those interested in headphone audio who write about it on the internet, very often listen to metal and EDM, in addition to various East Asian pop genres. This diversity in musical tastes is great, but it also changes how one might think about evaluating what counts as good sound. One cannot be brought to a live performance like performance at a jazz club that never existed. When listening to good quality recordings of live music, good sound was often understood to be something like making it sound as though you were at the performance itself.
Of course there have to be many qualifiers to this; one doesn't want to record some of the real features of performances, like excessive audience noise, air conditioning, etc. But in any case, one might find a reasonable middle ground to give the experience of listening to live music. Recording EDM, for example, is obviously a very different kind of thing, as is the recording of many genres of popular music in studio.
To me, good quality recordings of the traditional audiophile kind (not necessarily audiophile label recordings) with wide dynamic ranges, live instruments, etc, sound really superb on the NDH 20s. I've noticed the compressed sound of compressed recordings is much more obvious and intrusive on the NDH 20s than on my other over-ear headphones (Meze 99 classics and Oppo PM2s). If one listened to genres, or recording periods, where they were the norm, I could imagine that NDH 20s would not be a pleasing sounding choice. I wonder if this accounts for some of the wide range of reactions to these headphones. Perhaps they conform much better to the expectations of some types of listeners than others (said without judgement about those expectations, I should add).
More later. But thanks for an interesting discussion on this thread. I've just included the quote below to point to where part of the discussion I had in mind took place.
Impressions after a week or two with the Neumann's:
Weird headphones. Not sure if I love them or hate them. First thought after about 10 seconds of listening: They sell these as neutral monitors? They are NOT neutral AT ALL. Very boosted bass and rolled off trebles. But after 2 weeks, I have to nuance that first impression: I still think they are far from neutral (whatever that is), but for me, they work with some music, and not at all with other music:
What works: Older music, mastered in the 90's and before. In those time, tracks were being master in a "thinner" way, less dynamic and less bass. Old rock, pop, metal etc. works beautifully. The NDH 20 elevates the recording's thinner bass beautifully and dampens the sometimes harsh highs of those types of recordings. I genuinely have to say that I enjoy my collection of older music much more than ever.
What does not work: E.g. recent, well mastered EDM. Tracks that already have a strong bass component are un-listenable. Total bass overkill, especially, if the recording's bass contains more mid-bass than sub-bass.
In a nutshell, older, crappy recordings sound great, well mastered, modern stuff doesn't. Since a large part of my collection is old rock etc, I will keep the NDH 20 for those, for the pleasure of rediscovering older songs. And also, because I really like the build (like a tank) and the fact that they are quite portable for a full sized headphone.