Ok the DT990 Pro's get knocked a lot, personally I like them... they have much stronger bass compared to the DT880s, without having a completely insane amount of bass like the DT770's... it dosent have the details or resolution of the DT880's, but if you want the beyer sound, with more bass than the 880's without going to nutty bass land with the 770's the 990's are a good compromise... personally I am not a huge bass person so a pair of DT880's is on my xmas list :)

these cans really need an amp to sound nice, nothing nutty, a decent PIMETA or hell even a nice CMOY should do... of course the nicer the amp they nicer they sound... to a point of course... these cans are also a bit bright so avoid bright sounding amps/sources...