Hi all! I'm new in this forum, and also a newbie in the area of high-range headphones ... so, please forgive me if I ask stupid questions

.
The reason why I reply to this post, is that I'd like to buy a good headphone for listening to music while working in the office. After reading quite a number of threads in this nice website, I'm currently mostly interested in Ultrasone HFI-780. I just have a few questions

, that I hope you expert can answer:
1. I've seen many posts saying that HFI-780 has a lot of bass. I mostly listen to classical music, so I wonder if any of you have comments about HFI-780 for classical music. Would you recommend it? If not, could you suggest an Ultrasone alternative (I like their MU Metal shielding - ULE-technology feature)? Or any other alternative?
2. I was also interested in HFI-2400, but since it has an higher impedance (70 Ohm vs 35 Ohm of HFI-780) I suspect that it requires an amp and that I can't use it directly from an mp3 player or my laptop. Am I wrong?
Thank you in advance!