I hope I can listen to the t90's on a bottlehead someday to see how much they mellow out the t90's...
Seattle head-fi meet at Bottlehead next Sat will allow many that opportunity. An ODAC (standalone), O2, Crack and a T90 makes a great collection to enjoy both accurate and euphonic experiences. This is my transportable system, though the Concero HD has displaced the ODAC in my setup.
If anybody has something to say about T90+Crack vs. O2 , it would be nice (even though I'm sure Crack will outclass the O2)
It isn't a matter of outclassing, it is a matter of different presentation. The O2 falls in the accurate, straight wire with gain category. The Crack falls squarely in the euphonic class. If I asked which is better, a wide angle or zoom lense, everyone would tell me they give different presentations to the camera. Please don't take the wide / zoom analogy as a direct correspondence, it isn't. The Crack and O2 are, however, auditory compliments to each other.
I have both the Beyerdynamic DT-990 and the T-90. I had the same issue when I first got the T-90 they were cold from sitting outside. I then put them on and wow what a bad headphone. It was shrill with no bass at all. I was so disappointed. I spent a bunch of money to get an inferior sounding headphone which I wanted to return. Luckily I didn't send them back.
I was coming from the DT-990 which was already broken in which made the T-90 sound horrible. I then thought I needed to break them in, so I used an application to generate 30 hertz and left them running at a moderately loud volume for a week or so. I then came back and the bass was much more acceptable and more dynamic than the DT-990. The soundstage and the bass was much better after the break in. The soundstage opened up really big and precise you can virtually see the performers playing the instrument with your ears. I personally love a nice expansive soundstage and I will buy headphones capable of it. I also had to changed cables and power cords for my equipment which made a huge difference and smoothed things out so much that they sound awesome. I am using solid silver cables with no copper. I personally think copper or hybrid copper silver produce a harsh sound that has a peak in the midrange. I also changed the tubes to NOS for my Schiit Valhalla Amp for Amperex 7308 from Upscale Audio which makes a huge difference as well. The stock Valhalla tubes are a bit harsh sounding with rolled off high end frequencies which have a peak in the lower end treble which bothered me. If you hear harshness in the treble it could be your equipment or cables. You should try swapping them out for known smooth sounding cables and equipment. It may change your opinion about the T90's because they are awesome sounding I would never go back to the DT-990.
keep listening , you're just at the tip of the iceberg !!! hahaha ! be prepared for the insane potential pack in the T90 !