The LOWER the impedance, the louder the headphones. The lower impedance models (in my opinion, I haven’t read Beyer’s copy) are made with studio work in mind, for example listening to tracks as you are playing and recording drums, which are quite loud. For simple listening, the 250ohm pair of DT700 (for example) would be great. I own a pair. They are plenty loud and sound great.
I am an audio engineer with 20+ years experience.