Hi, I'm thinking about buying a Fiio E12f or my DT 990 PRO 250 ohm's, but I'm not sure if its necessary because through my iphone 4s, the volume is very high, way higher than what I listen to and I feel like the bass and soundstage is very good, I like the highs too. But everywhere I read people saying these headphones really need amping. Without an amp, these headphones would have sound quality compared to 50-100 dollars headphones people claim. I thought an amplifier only made it louder? What else would the E12 improve on?