So i have been looking for a open back headphone for the past couple of weeks to upgrade from my hyperx cloud 2 which i have been using for last 2 years. After going through a lot of guides and articles i have finally narrowed it down to mainly 3 choices 1. Sennheiser hd 5992. Beyerdynamic dt 9903. Audio Technica ad 700xnow i mainly use headphones for gaming, mainly fps like r6s,csgo,bf and i listen to a lot of rock music.Which one of them would be suitable for my purpose and if anything is better at that price range then feel free to suggest. And my mother board is rog maximus vii hero which has supreme fx sound card so do i need an amp/dac to run them?i have absolutely no idea about it, any advice will be appreciated.Thanks in advance.