I have tons of respect for Sennheiser's HD6x0 headphone lineup, as you can tell from my previous Den-Fi content. They are the consummate all-rounders of our hobby, and their value proposition has made them the most legendary audiophile headphone of all time.
My personal favorite of the line is the HD650, known for its smooth, warm presentation that is by many accounts incredibly difficult to hate. It serves as the tonal benchmark, regardless of price, and it has both earned its legacy and defended that spot at the top for 20 years now.
Neumann is another company with a similarly great—if not greater—legacy in audio than Sennheiser. They are known best for their Ux7 line of microphones (U47, U67, U87 etc), which are the most storied condenser microphones out there. Even with this legendary status, there are at least two things many people don't know about Neumann.
First, many don't know that Neumann is actually owned by Sennheiser. Second, most don't know that Neumann makes headphones.
I've had a chance to try one of their prior offerings and was not a fan. The NDH-20 closed back headphones had an upper midrange that sounded particularly sucked out in a way that made everything sound smeared and lifeless.
I was recently sent Neumann's newest effort in the space, the NDH-30 open back headphones, and I was very excited to receive them.
Maybe it was being such a fan of their sister company's headphones, maybe it was the fact that I'd seen measurements from Oratory1990 prior to it being sent to me (and that it looked very good), or maybe it was just me being excited to hear new stuff, but I had a lot of hope for NDH-30... and I'm disappointed with it after continued testing. Let's talk about why.
Build & Comfort
The build is exceptional feeling in the hand. Much of the design here is metal and feels sturdy any way you choose to hold it, echoing Neumann's own NDH-20. The headband feels like a pliable, but stalwart metal dual-rod architecture—similar to the Fostex/Denon headband—containing a rather stiff 2-bump headband pad. The earcups are hard metal. The look overall is what I'd call "fine" for my personal tastes.
There are a few things that confuse me though. For one, this is a $650 headphone and the cable connection is single entry... on the right side. I really don't know what was behind either of these decisions, frankly. Most headphones in this price range are dual-entry (which I prefer), and of all of the single entry headphones I've ever used, I've never seen one that can only be plugged in on the right side. This definitely took a bit of mental adjustment to get used to and even now after having NDH-30 for weeks, I still get caught putting it on backwards sometimes.
It's especially annoying given that the included cable is an excruciatingly long 10ft cable. No one needs this much cable in 2023, neither audiophiles nor mix engineers.
The comfort is unfortunately poor for me. The ear cups are adequately spacious circumferentially, but not quite as deep as I'd like. My ears touch the inner baffle, but the front damping foam is sufficient enough to not make things immediately uncomfortable. The weight overall is lighter than I expected given the all metal build, but it's still a bit too heavy for me. Especially because my biggest complaint is the headband padding.
It actually reminds me a lot of HD650's headband pad, but stiffer and wrapped in a rubbery-pleather type material. I'm not a fan of it at all and the discomfort begins almost immediately; the "nuggets" dig into my head and create a hotspot within minutes. They simply don't have enough front-to-back surface area to distribute the weight anywhere other than two very small nugget-shaped craters on the top of my head.
Overall, NDH-30's build and comfort doesn't strike me as a complete nightmare... but it's pretty bad. At $650 I'd really hope they'd have figured out the basics: audiophiles like suspension straps, dual-entry cables, and deep, ear-shaped earpads/cups.
Frequency Response & Tonality
You might say: "Wait that looks pretty good... How are you disappointed? Don't you always talk about how much you like dark headphones? Don't you always say how you like a warmer midrange?"
Honestly, I'm as confused as you are. On paper, purely on the basis of frequency response, I should like this headphone quite a bit. My initial excitement before receiving it was basically entirely due to these measurements that made it look like an HD650 with slightly warmer mids and less treble.
However NDH-30 has stepped decisively over the line from the "warm, smooth, relaxed" territory of HD650 into somewhere completely different... and worse.
The bass is well extended with a low frequency resonance bump reminiscent of Sennheiser's HD560S, one of the better features here for sure. The bump isn't of an exceedingly wide or narrow Q, and as such, most instruments' low end character is normal sounding. The biggest problems with the bass aside from technical aspects mainly make themselves known regarding how bass interacts with the other areas.
The lower and center midrange are similarly problem-free, as they're linear with no major aberrations that cause imbalance between harmonic and fundamental. But once you get above 1kHz, problems begin to make themselves known fast.
That big dip centered at 2.2kHz is really, really a shame. It is the most noticeable and glaring flaw to me personally. This dip makes male vocals sound especially hollow and sedated vs. my other headphones. Acoustic guitars lack pick-click and definition, electric guitars are missing core elements of their texture (bite, clarity, richness), and snare drums sound like they're being played with rubber mallets instead of drum sticks. This 2-4kHz octave is most sensitive area of human hearing and when you're met with NDH-30's deficit in this area, it shows.
It's almost as if the rest of the frequency response so far up to this point is so unproblematic that it makes the big dip harder to ignore. It's to the point where there's almost an "uncanny valley" effect at play. Once anything tokening the midrange happens (usually within the first few seconds of a track), it's impossible not to notice the one big flaw that makes you question how you were ever almost fooled. I can't stress enough how shocked I was to be so bothered by this one dip since on paper this still reads as a mostly good frequency response to me.
Lastly, the treble. As a vocal advocate of darker frequency responses in headphones (in a hobby seemingly dominated by treble-forward "detail cannons"), this is simply too dark. I'm usually not one to complain about lack of treble... but these headphones are about as dead as anything I've ever heard.
Resolve from Headphones.com called these "dull" within seconds of hearing them, and I can confirm, it is immediately obvious how dark they are. For the life of me I can't think of another headphone with a treble response quite as occluded and blurry sounding as NDH-30. It's actually a little upsetting that the dark treble—the single thing I was most excited for about it—ends up being one of its biggest problems, even for me.
With respect to timbre, I don't sense any glaring problems with unnaturalness due to material related quirks... but something is still very wrong here.
Most of the problems I have with NDH-30 sounding not particularly lifelike can be traced directly to its frequency response quirks (especially the ~2kHz dip), but that's not all.
To put it simply, it sounds like I'm listening through a mountain of front damping foam.
No matter what instrument, NDH-30 sounds like a JPEG that's been copied, reprocessed, and pasted about 40 times too many. Nuance and textural resolve are all either blurred, aliased, or straight up gone. The sense of contrast between distinct parts of the music is flattened into a soulless, darkened monochrome that makes it really hard to emotionally or intellectually engage with the music.
Speaking of contrast, NDH-30 can portray a reasonable amount of thud when it comes to kick and snare drums, certainly more than something like Sennheiser's HD560S...
Unfortunately though, the decay here is almost completely suffocated to the point where distance between loud and soft is almost entirely erased. Things have a somewhat pleasantly rounded attack transient, but tails are so blunted that the actual energy behind hits disappears almost immediately.
To that end, the treble rolloff here definitely contributes to NDH-30 being one of the most detail-less, micro-deficient presentations I've ever heard. There is no conversation to be had about microdynamic swing, small gradations of volume between little low-in-the-mix elements, or "detail." NDH-30 has as close to none as I've ever heard, trading blows with the Koss PortaPro in that regard.
Soundstage & Imaging
This is probably where NDH-30 compromises least, but even then it's not exceptional.
Unlike HD650, the images are never really in-your-face or overbearing. The sense of distance available to play with is about on par with the new Meze 109 Pro, if memory serves.
The problem though, is the imaging. NDH-30 really struggles when it comes to separating images or giving things their own space in the mix, allowing them not to be tread on by elements in close proximity. The presentation here is smeared, blurry, and a little stretched, but overall not my biggest problem with NDH-30 by a long shot.
Unfortunately, comparisons are where things go from somewhat poor to downright grim for NDH-30.
Especially since HD600 and HD650 are less than half the price and absolutely clobber NDH-30 in basically every important way.
They're more comfortable, with a better industrial design than NDH-30. They're arguably the best tuned line of headphones in existence, and the best timbral experience in headphones at any price. Dynamically, they're perhaps nothing special, but they still beat NDH-30 overall in contrast (in both a macro and micro sense). HD6x0's separation is another highlight at it's price, and it's definitely better than NDH-30 in that regard too.
The only benefit the NDH-30 has over a ~$300, 30 year old headphone made by the same parent company is... soundstage. Perhaps unsurprisingly, that's not nearly enough for me to feel comfortable with it as a product.
I will say that NDH-30 is better overall than NDH-20 at least, so I guess Neumann is on a mild upward trajectory in their own lineup. However, there is still a ways to go.
After all this time testing, frankly I'm just not sure who NDH-30 is supposed to be for. It's an open back headphone, which to me says "audiophile" more than "pro audio/engineer." But it doesn't do anything for either use case that would justify paying $650 for NDH-30 when you can pay 30% of that for an HD650.
I really wanted to like NDH-30. As a huge fan of HD650—save for one treble peak at 10kHz—a warmer/darker HD650-type headphone seemed like it would be absolutely perfect for me.
But it's just too warm, too dark, too bleh. The build is worse than HD650 while being more than twice the cost, and the sound is even more upsetting.
It seems NDH-30 has the unfortunate fate of being, well... like most dynamic headphones: Overpriced for the sound quality you get, and destined to live in the shadow of the tone, timbre, and value king that is HD600/650.