No review or impressions. I did talk about them in an email to a friend, if anybody's interested.
"Not sure just what I expected with the DT990, but it wasn't this! The DT990 is the open version of the DT770, so I anticipated bass. I have that. Listening absolutely flat, no EQ, no bass boost, it has a nice thump to the lower register. I started off with a wind band recording that's one of my reference discs. The Beyer was made for this music, laying down a solid floor in which the music sounds securely rooted. Better yet, this is articulated bass, no subwoofer bray to it. A drumroll resolves into individual beats and I suddenly recognize not just a single instrument but two. Not as quick on its feet as the SA5K, (what is?), but the control makes the HD650 seem blurred in comparison.
"Now here's where it gets weird. My wind band disc is a reference because the first cut includes a cymbal at one point that can sound like a dropped flatware drawer when badly reproduced. The Beyers give me a lovely metallic splash. Nice. Switch to an anthology of British light music for orchestra, a beautifully recorded Hyperion CD I know like the back of my hand. Where did all this detail come from? I'm hearing little things I've never noticed before. A background triangle appears for a brief glittering interlude. I turn the volume down a bit and press on. The sound is forward, typically Beyer, a bit bright and just the way I like it. Funny, lower volumes are just as clear, as detailed, as articulated. Nothing gets lost in the mix. The mids remain front and center, balancing the glitter on top and the thump on the bottom. Of course, this may all be due to emphasis designed into the cans, which would make them anathema to the purist, but I rather like what I'm hearing. This is a fun listen. Less refined than the 880 but more lively. Chamber music is beautifully detailed, no suggestion of what lurks in the bassy depths intrudes.
"Probably belongs in the weird category as well. Soundstage. Interesting sort of semi-surround sound kind of effect. Not like the DT880s, which is wider, but more like a hemisphere spread out in front of me.. Doesn't sound exaggerated at all. It's not a "look at me" sort of effect. Frankly it reminds me of near-field speaker listening. Very different from the piped-in sound I associate with the Senns, for example.
Tried some cello, since if anything should reveal an intrusive bass it's the lower register of that instrument. Not a hint of shading or darkening. The Yo-Yo Ma/Marricone recording spends a lot of time way down low, and the bass remains firmly in place. Neither am I encountering the recessed midrange that some have reported, but I'm keeping an eye out. The Dire Straits/Telegraph Road disc is probably a poor test because Knopfler always sounds recessed as a vocalist on that track. On the other hand, it certainly demonstrates that the DT990 can thump. Hard.
"After five days, the cans seem to be mellowing a bit (or I am). The bass is less prominent and the balance seems to be shifting toward the DT880s. Detail continues to be striking. So does the soundstage. I notice it especially when I switch to either the K501s or the Sonys. The Beyers are warmer and, yes, bassier, but the sound seems to enfold me with an ambiance I find attractive."
BW