I recently bought a pair of DT700 Pro X thinking they would be a substantial improvement over my 2008 ATH-M40fs but I was kind of disappointed. They sound like crap to my ears without EQ (boomy, underwater, muffled). Then I came back to my old pair, also thought they sounded like crap without EQ (harsh, absent bass). I took the time to EQ the DT 700, then took some more time to EQ again the M40fs, and the DT 700 is not much of an improvement, not for the price paid. They sound decently good with an EQ, have a little bit better imaging, separation, soundstage, comfort etc. but I expected better stock sound for the price.
Maybe my expectations are unrealistic and I should up my budget a bit and get closer to real hifi instead of staying in the mid-fi class?
What are you plugging the DT700 Pro X into? If the headphone amp has a high output impedance, you will hear exactly what you have described, a boomy bass boost.
The headphone jack of my Steinberg UR22 USB audio interface
Just copied from Google: A common rule of thumb is that the output impedance should not exceed 1/8th of the nominal impedance of the headphones. So, for 300 Ohm headphones, you’d want no more than 37.5 Ohms output impedance; for 16 Ohm headphones, no more than 2.
OMG! I just tried the DT 700 Pro X in the headphone jack of a laptop and they sound completely different. No boomy bass boost.