New DT770 Mixed performance..?

I bought some new beyerdynamic dt770 pro 250OHM headphones. I have had them for 1 day and they have had really mixed performance. I am not sure whether they are faulty, or if it's my sound card or what. I will be getting a fiio e7/e9 combo which will eliminate the sound card form the equation. At first the highs sounded very sharp and piercing. They calmed down a bit after a couple hours. They seem to change in sound a fair bit. I'm not sure if this is normal because they are not broken in yet or not. Some frequencies seem to give me a static kind of sound, but I am not completely sure of the tracks. This is much much worse when I tried my laptop, there was static almost the whole time. I asked a question about what quality I should set my headphones to in the settings. Nobody has answered after a couple days. It would be great if someone could tell me where I can get some free lossless reference tracks. Dubstep or rock kind of music would be preferred, but other types will do. I am trying to find some music that has a wide range of frequencies, specially high lows to mids as that is where the problems seem to be appearing. The only lossless songs I have right now are Nero's Welcome to reality Album. Could be a bad source though, I'm not positive. Thanks for your help in advance :D 

I think it might be problems with source. I changed to winamp and I tried some Michael Jackson albums and they don't seem to have this. I suppose it will be more clear once my DAC and amp arrive. The headphones definatly changed in sound. Either that or they where so piercing that I am now deaf to those frequencies but I doubt it.