Argyris
Head-Fi's third most long-winded poster.
For me while this headphone mostly has a pretty awesome sound (I have the 880 pro), the highs are just too shimmery and bright for me, from the graphs there's just too much energy between 6k and 9kHz compared to the rest of the frequencies. 600Ohm version seems to have a little less energy there, so maybe I'll try it once if I get a chance, but most people say the difference isn't huge.
Right now I am too looking to try the HD600 again, probably it sounds similar to the 650 but from what I remember it was also a lot more neutral so I'm thinking it should respond a lot better to EQ than for example the 650 or DT880 do. Am also looking at one of the older hifimans 400 or 500 (the newer versions like 400s and 400i seem to have a bit of a stale sound and seem to lack some upper treble), hopefully I can find a used one soon.
Right now I'm using the cheap but very decent sounding K240 Studio, although the expensive AKGs seem to have a similar problem as the 880: a bit too much mid-treble energy combined with a lack of body in the bass. I kinda wanna try the old K240 Monitor though.. And I wanna try those vintage Beyers too some time, I'm wondering though if they were less bright sounding..
The DT880 responds brilliantly to EQ. It needs to be targeted parametric EQ, though. A graphic EQ isn't going to have fine enough control, nor will it offer the specific frequency bands needed. This of course means you're stuck using a music player that supports a parametric EQ plugin, which isn't always practical.
If you're up for it, the trouble spots on the DT880 are centered around 6 kHz and 8.5 kHz. Bringing the former down by around 7.5 dB and the latter by around 6 dB (both notches of 0.3 oct bandwidth / a Q of 4.8) is a good place to start.
If this sounds like too much trouble and you want to go the HD 600 route, I can tell you that, apart from lacking the elevated lower- and mid-treble of the DT880, in direct comparison the HD 600 also has a bit more upper midrange presence, less bass extension, and less prominent upper treble (though with similarly excellent extension as the DT880). The effect is that the HD 600 sounds mid-centric in comparison to the DT880, which is a bit treble-focused and has slightly more prominent bass but more subdued upper midrange. It took me a bit of getting used to coming straight from the DT880, but the HD 600 is a truly excellent headphone. My DT880 has been pretty much shelved since the HD 600 arrived many months ago.