First things first - the amplifier appears to be not functioning correctly; at the halfway point and below, it seems to work properly, but as soon as the volume is turned above halfway on *any* channel, the sound gets muddy and low-toned only and reverts to single-channel...
First things first - the amplifier appears to be not functioning correctly; at the halfway point and below, it seems to work properly, but as soon as the volume is turned above halfway on *any* channel, the sound gets muddy and low-toned only and reverts to single-channel (right or left depending on headphone used). Huge bummer. Just get the normal set of headphones as I''m not sure if returning just the amp will be worth it for me. I have never heard of Knox before but have limited experience with headphone amps in the first place.
To compare these headphones adequately, I have used the following pairs of similarly-priced sets and will try to express opinions in relation to these so you have a reference point of my experience: Grado SR-325i, SR-225x, SR-80x, SR-80, Sennheiser HD600 (older), Audio-Technica M50, and many other Sony headphones and miscellaneous brands here and there (nothing priced much over $300 as that''s my personal limit).
First off, I feel that the sound signature on the DT 990 250 ohm headphones is quite unique. If HD600 is a "true neutral" category (which I and many others feel it generally is) and Grado makes headphones that are punchy and wide-sounding (not even slightly neutral, which is a generally desired effect) I have to say the Beyerdynamic ones featured here sort of split the difference. They are bright and a bit "overly crisp" and in that way aren''t quite a true neutral like the Sennheiser HD600, but honestly I love getting a different sound from each of my sets of cans, and this one fits that bill.
And now for a bit of reservation: the sound coming from these is almost *too* sharp or bright (seems to be emphasizing high hz) to have the volume turned up for long, specifically when I listen to 8-bit style music where those high pitch triangle instruments can add quickly to ear fatigue. I''m going to wear them in and play some tunes for a few nights to see if this changes. If the sound starts to get a bit more mid- and bass-heavy or balanced as does often happen with new cans, I''ll try to update this review to reflect that. Note: these are still awesome for the price.
If you want more bass (only a bit more, and that is once they are worn in), AT-M50(x) may be more where you want to go, but for those to be this comfortable you''ll need velour custom earpads. I also don''t think they''re as durable as these, from the feel of things.
If you want more true neutral, HD600 (or similar) comes recommended. If you want a beautiful wide sound stage and you don''t care as much about neutrality (or comfort since Grado is by far the least comfortable, imho), I recommend checking out SR-80x or SR-225x (Grado''s entire line has a similar sound stage effect, clearly part of their signature). However, Beyerdynamic has achieved something very special here, as the brightness sounds very special in the right tracks - fade- and gate-heavy music like techno seems to have an absurdly fast bass-to-nothing-to-bass type of response with these - they''re *fast* at those transitions, and that really is awesome.
There is a small amount of sound isolation on these DT 990s even though these are technically open ear. I''d probably say they''re 75% open ear, 25% quieter than usual open ear type cans. I find the earcups to be very comfortable and close to the Sennheiser HD600 which are, imho, my most comfortable headphones as I can barely tell when I have them on. For the price (without this included amp, they''re going for around one fifty right now), these are still an excellent pair of headphones. I am absurdly picky, but these provide something unique in my collection, for sure, so I''ll be keeping them for a long while.
I do not know what difference the 250 Ohm vs. standard driver setup makes. I went for the 250 Ohm since everyone seems to state there is some sort of difference in its favor and my equipment has no problem driving high amplification and volume to get past these sorts of limitations. Happy shopping. I don''t think anyone would be angry with these headphones, quite honestly. I think the mids and bass on these will improve with playback time as it often does and right now it''s at least "good enough".