Just want to say that the dt990-32 ohm that I used to own gave me tinnitus when i listened to them for over a few seconds, It's not even funny. They should put a warning label on them saying that these headphones are for people that want to test if they have ears made of steel.

I've heard that too. The 32 ohm that I had was supposedly even brighter than the 250 ohm though hehehe.

Amazingly the DT990-600 were very nice!

After some EQ anyway.

They tend to make guitars sound too shrill and high-pitched.  The soundstage and bass is great for movies as well.  OTOH they make Kugi lolis amazingly painful.

http://en.wikipedia.org/wiki/Rie_Kugimiya

As soon as Shana opened her mouth I knew they were going back.

Of course that assumes the ones I had are anything like the ones you heard.  The 880s and 990s seem to be more consistent but this is Beyer we're talking about.

My eq settings for DT 990 pro 250 Ohm(bought in ~2008). EqualizerAPO(free) or similar software/hardware needed. PK=Parametric EQ:

Filter  1: ON  PK       Fc     403 Hz  Gain  -6,7 dB  Q  1,00
Filter  2: OFF  PK       Fc   4.654 Hz  Gain  18,0 dB  Q  3,04
Filter  3: ON  PK       Fc   1.527 Hz  Gain   5,9 dB  Q  1,03
Filter  4: ON  PK       Fc   7.025 Hz  Gain  -6,7 dB  Q  1,79
Filter  5: ON  PK       Fc     730 Hz  Gain   9,4 dB  Q  3,06
Filter  6: ON  PK       Fc   2.302 Hz  Gain  -3,8 dB  Q  2,34
Filter  7: ON  PK       Fc     102 Hz  Gain  -3,1 dB  Q  2,00
Filter  8: ON  PK       Fc     164 Hz  Gain  -3,0 dB  Q  2,00
Filter  9: ON  PK       Fc    66,0 Hz  Gain  -2,9 dB  Q  2,00
Filter 10: ON  PK       Fc    43,6 Hz  Gain  -2,7 dB  Q  2,00
Filter 11: ON  PK       Fc   5.159 Hz  Gain  -8,2 dB  Q  6,39
Filter 12: ON  PK       Fc     953 Hz  Gain   4,1 dB  Q  3,45
Filter 13: ON  PK       Fc     456 Hz  Gain   4,5 dB  Q  4,97
Filter 14: ON  PK       Fc   5.695 Hz  Gain  -4,4 dB  Q  4,89
Filter 15: ON  PK       Fc   3.959 Hz  Gain  -4,9 dB  Q  5,45
Filter 16: ON  PK       Fc    31,2 Hz  Gain  -2,1 dB  Q  2,48
Filter 17: ON  PK       Fc     648 Hz  Gain   3,3 dB  Q  4,69
Filter 18: ON  PK       Fc   4.307 Hz  Gain  -4,3 dB  Q 12,57
Filter 19: ON  PK       Fc     578 Hz  Gain  -1,8 dB  Q 13,25
Filter 20: ON  PK       Fc     557 Hz  Gain   0,5 dB  Q  4,95

Filter 21: ON  HS       Fc   6.000 Hz  Gain   3,0 dB

Automatically generated settings(REW) except for filter 21.
I consider this (seemingly weird)result as more accurate than stock HD650.
At first I thought it was placebo. But after many hours of listening to almost anything(including dolby headphone material) I still prefer this sound tonally(although there seems to be a little sibilance around 10Khz, because the correction was limited up to 8Khz). Main improvements include clearer/more present mids, less boomy midbass and very low fatigue(an indicator of good sound in my books).
I would like to hear other owners' opinions.

My take on the DT990 Pro in 250Ω impedance.

This one has black velours pads, these pads measure exactly the same as the grey DT990 pads.
These headphones are very comfortable and have a decent clamping force, slightly higher than the edition version.

The cable for the Pro version is partly curled and rigid. Not ideal when using it on the go but it is not intended for that anyway.
The coiled cable is better suited for studio work. The plug is 3.5mm and comes with a 6.3mm adapter.

Below the frequency response of the DT990Pro (left, right):



This represents pretty well how it sounds. It is U-shaped and has lots of 'warmth' and is bassy. It also has a LOT of treble energy up top.

Below the CSD of the stock DT990Pro - 250 (left, right) It is actually pretty decent and doesn't show any long lived resonances that may be problematic.