I did a comparison between the Amiron and the DT 1990 back in 2020 in another thread. I will copy and paste what I posted here.
In terms of sub bass, both headphones are about equal. With the mid bass, the Amiron is more elevated. When using the DT1990 with the analytical pads, it does not have any mid bass bump at all. It is rather flat across the entire bass range up to the lower mids. With the balanced pads, there is certainly a hump there. I am not a fan of a mid bass hump on a headphone. I really dislike when mid bass bleeds into the mids on a headphone. I will always EQ this down on a headphone which has it with stock tuning. Even when comparing with the balanced pads though, the Amiron mid bass is still higher and broader in its elevation than the 1990. It bleeds into the lower mids more. Overall, the DT1990 has a faster, tighter, and more engaging bass. It has fast decay in the lower bass frequencies, and is not boomy at all. Both headphones need a mid bass reduction to sound correct though (if using the balanced pads on the 1990). With the analytical pads, the mid bass on the 1990 is completely flat. The bass on the Amiron is warmer and softer across the range. It has a bit of a loose character to its presentation. Keep in mine I am comparing the Amiron against the 1990 with the balanced pads though.
With the mids, the Amiron is more layed back. It is recessed in the mids, partially from that heavy mid bass hump that bleeds in. The Amiron is recessed from 1kHz to 5kHz. Vocals are layed back, and not harsh at all. All of the detail is there. Instrument location is correct. The soundstage is vast, and imaging is excellent. The Amiron offers all kinds of details in the music that most other warm headphones just do not produce. It really is a unique headphone. With the mids being recessed though, there is a sense of distance between you and instruments, as well as the vocals. Nothing in the music is up front at all. The Amiron is not designed to offer a dynamic and energetic listening experience. It is all about sitting back with a quality beverage and enjoying a relaxing listen with the music of your choice.
With the DT1990, the mids are a tiny bit recessed, but only just slightly. Instruments are more defined and up front. Vocals are not layed back. They are right in the center of your head. Imaging is pinpoint, and extremely accurate. Like the Amiron, the DT1990 also reveals all kinds of details in music, but it does so with even more focus. It demands your attention. Soundstage on the DT1990 is slightly less wide than the Amiron. The 1990 is certainly not narrow though. In exchange for it being not quite as vast as the Amiron, it gives you a more focused and realistic presentation. Instruments on the DT 1990 have better separation and layering. The Amiron is already good at detail retrieval. The 1990 pushes this a step forward. Nothing in the music is able to hide from you.
Regarding the treble, as we all know, the Amiron is certainly more layed back. It is not a bright headphone at all. The treble response is clean, non-fatiguing, and organic. This is a headphone that you can listen to for hours. In my opinion, it could use a little more extension in the upper treble. It is slightly rolled off in the highest frequencies. This is a headphone that you can easily turn up and get blasting because it just has a relaxing sound signature. I can not imagine anyone claiming this headphone is bright or piercing. If that is the case, the person needs to get their hearing checked.
With the DT1990, the treble is more detailed. It is certainly brighter as well, and not layed back. It is a bit too bright between 6-10kHz. As a result though, every detail that is present in music is exposed. Just like the Amiron does, the DT1990 also exposes clicks, distortion, pops, sighs, bangs, echos, grain, and any other defect that is present in recordings. The difference between it and the Amiron in this regard is that the 1990 will not ever leave you guessing if you just heard something. You will immediately say "wow, I have never heard that popping sound there before, or that thumping noise in the last track". From top to bottom in the frequency response of this headphone, the 1990 just hammers you with details.
My genres are hard rock and heavy metal. For this type of music, I think the DT1990 is the better headphone. The reason for this, is because it just attacks the music. It pulls all the detail out of it. Instead of the headphone saying " I am going to let the artist show you what is on the album", the headphone says "hey artist, you sit back, and let me show the listener myself". Guitars are engaging, and have a nice bite to them. Instruments sound layered, and details are pushed forward. It is a real toe tapper of a headphone for heavy styles of music. The thing is though, for anyone who has not heard either headphone, I actually recommend both headphones, unless you have a specific sound you want. If you want a headphone that has pinpoint imaging, is engaging, and has up front detail retrieval, the DT1990 is a great choice. If you want a more relaxing listen, where you want a sound which is reminiscent of listening to vinyl, then the Amiron is a great choice. If you want both of these experiences, then I recommend both headphones.
