Okay, I can try to. I'm going to start where I find the two headphones are similar and what strengths they share. I am comparing the HD 600 and the DT 1990 with the 'balanced' pads(which offer a bit more bass and is more intimate), the analytical pads remind me a bit more of the T1 Gen 2. The whole reason I got the DT 1990 is because of the DT 1770 which reminded me a lot of the HD 600 and I was hoping Beyer finally released a new neutral open-back and it seems yes they did.
Okay as to what these headphones share in their strengths, is neither are sibilant, sound harsh, both scale well with gear, and they sound good with all genres of music but truly shine higher quality recordings. Both headphones are genre-masters. Because of these similarities I feel the headphones compete with each other as non-fatiguing natural sounding all-rounder open-backs.
Amplification: First I am going to talk about amping the headphones. Both share a similar ohm rating, Beyers being 250 ohms and the Senns 300 ohms, but the Beyers are very sensitive. Because of this sensitivity they Beyers sound great directly out of a phone, laptop, etc. making it much more versatile. But because of this sensitivity they pick up a lot amp and system noise, in fact as much noise as my 25 ohm Nighthawks do, so a low noise floor is a must with the DT 1990. The solid state Sony UDA-1 is my amp of choice with the HD 600. My amp of choice for the DT 1990 is the Project Sunrise III with a JJ gold-pin ECC88 tube. The DAC on both is the Sony UDA-1 via USB and Optical.
Comfort & Build: In terms of build the DT 1990 feels a lot more premium over the HD 600. The DT 1990 has a somewhat heavier and notably more robust feel to it's design, due to it's metal and more premium materials. Pads, this is where I feel the DT 1990 really is better, the soft velvety memory foam pads are just so comfortable, the pads on a new HD 600 feel a bit stiff, hard, and a little scratchy in comparison. That and I expect the DT 1990 to last longer since the foam in the HD 6xx has a tendency to deteriorate over time. Comfort is subjective, I do find the DT 1990 to clamp slightly more than the HD 600 but I like how it distributes weight more and the clamp doesn't bother me. In terms of repairability, both headphones are easy to repair as both are very modular. But the HD 600 has the edge in terms of replacing the headphone in terms of ease to do. The biggest caveat of the DT 1990 is it can't run balanced without modification as it uses the same connector as the AKG K7 series. I don't have a balanced system so it's not of importance to me currently.
Soundstage & Imaging: To start with on the sound, I'm going to talk about the soundstage and imaging. In terms of soundstage width and size I found both relatively similar in size with balanced pads, the DT 1990 with analytical pads is notably wider. Imaging is where the sound differences between the two headphones really start presenting themselves. This is where the DT 1990 completely outclasses the HD 600. The HD 600 has a bit of a softer and less defined edge around the instruments creating a somewhat blurry less defined edge around the sound image. Think HD 600 without anti-aliasing on games vs DT 1990 having anti-aliasing on games. This and the image of the DT 1990 is bigger and more present making the image of sound a bit smaller on the HD 600. You simply get a clearer and bigger picture of the sound image with the DT 1990. Both headphones offer exceptional center imaging.
Speed, Detail, & Decay: The next category is speed, detail, and decay. To start with, let's talk about speed. The HD 600 is a pretty fast headphone, faster than some people give it credit for, it doesn't really have trouble keeping up with more complex passages, but can start blurring on certain passages. I rate it faster than the DT 880/990/150, etc. and slightly slower than the K7 series. The HD 600 is slowest in the bass, the mids and treble are notably faster. The DT 1990 is actually much quicker in the bass, and faster in the mids and highs. The HD 600 can give an impression of being slightly slow at times while the DT 1990 never gives this impression. Now to detail, both headphones are quite detailed, but I hear more of the subtle cues in music, background noises, the tonal shifts a bit better in tracks, etc. I'm finding the DT 1990 beats out the HD 600 in both macro and micro-detail. In terms of decay I find the HD 600 has a slower decay than the DT 1990.
Dynamics, Transparency, & Musicality: Dynamics between the two, the DT 1990 is much more dynamic and robust throughout the who frequency spectrum, it makes the HD 600 sound a bit thin and flat in comparison as the dynamics give the DT 1990 a lot more body and tactility including the mids. The Beyers have a very hefty and robust sound to them, the HD 600 is softer sounding overall. Both headphones are exceptionally transparent to my ears, I find I forget I'm listening to both headphones and don't think about whether I'm listening to headphones on either. I will need to spend more time to determine which is more transparent. In terms of musicality I am finding both musical, but everything just sounds sweeter and more engaging on the Beyers to my ears, I guess it's better to say the Beyers are more euphoric, just makes music listen a joy and you stop caring about anything but the music.
Bass: Bass on the DT 1990 has a solid, snappy, and quick feel to it with excellent slam. It's articulate and detailed and I can tell what type of drum, etc. better than with the HD 600. It also extends better into the sub-bass, more akin to the Nighthawk in terms of extension. The HD 600 sounds a bit more bloomish and less articulate in the bass, but I find the HD 600 does have good bass, just not the same level though.
Mids: On a good system I find the mids quite intimate on both headphones, the mids are a little more forward on the HD 600, but the more tactile and dynamic mids more than make up for it as I find everything has more presence on the Beyers. Both have excellent tonality and timbre in the mids, though I do find the DT 1990 to my surprise was a bit better to my ears, that's what surprised me the most as I wasn't necessarily expecting that since the HD 600 is so good in this aspect. I'm able to hear the tonal changes more and the vocals and instruments seem more like they are there on the Beyers. It's interesting comparing them as the mids sound different on both but so natural on both. Both have a slight warmish tuning to their mids.
Treble: This is one of the more different aspects of the sound, both are very smooth and articulate in the treble. The treble on the DT 1990 sounds more natural on cymbal crashes and the like and has a bit more bite but doesn't sound peaky or anything. The thing with the DT 1990 it doesn't have much of what people would call "air" to it. Rather it has that clean smooth treble that only truly presents itself when needed such as with female vocals, brighter instruments, etc. The HD 600 has this more airy laid-back feeling to the treble but like some people have mentioned doesn't quite get the treble right on some instruments.
Hope this review helps anyone curious about how these two headphones sound in comparison. I'm trying to be the most objective as I can and tried my best to volume match the headphones to make the comparison more fair, using the same system and the system where I feel I get the most out of both. And getting adjusted to both headphones sound. Different systems may yield different results and this is based on my system with a wide range of music from classical, rock, metal, edm, hip-hop/rap, instrumental, experimental, new age, acoustic, etc. Preference of course matters. I personally feel the DT 1990 is an upgrade to the HD 600 to my ears. The DT 1990 is more like a super DT 880 with a HD 600 flair to it than a super DT 990 to me but quite different in it's own right, I doubt there will be any DT 1880. I am curious about the DT 1990 and Elear comparison.
