CTR640
Headphoneus Supremus
So that's why the T5p has more elegant and slick looks compared to T1.2 but that's just me. When I didn't had the T5p, I was looking all days for a solution to use the T1.2 for eveything. Today haven't found any except portable bluetooth adapters and batteries will degrade over time. It would end in frustrations and like you said, they Beyer indeed felt the pressure. If the T5p and T1 are super close in sound signature, then Beyer sure did a very good job! Todays it won't be any good if a lot of headphones are 600ohm considering people wants to drive them with ease I think.I think the T1.2 came out first and then Beyer feels the pressure to release something with lower impedance to catch up with with audiophiles' portable trend including DAPs and DAC/AMP. Very few headphones on the market today has a 600 ohm impedance compared to the past. That said, the T1.2 sounds excellent on my Kann Cube and I did justify purchasing it as the only portable gig that can drive the T1.2 properly without a desktop system.
I never tried the DT770/880 but I can say the brightest I have ever found in Beyer headphone was the DT1990 Pro....sold it 3 weeks after purchase. I learned my lesson.
I learned my lesson too. For now on, each time I want to get a new, I'll ask the owners about the treble peaks. It sounds like ear armor piercing treble from 770/880 :/