It's not a world-beater, but it's not bad either. I've been getting good results out of Headroom MicroAmp/Desktop Module. With that amp, bass is strong, mids are decent, and it's got some highs. With the wrong amp, the midrange sounds flat and there's no dimensionality. My best results have been with some very expensive tube amps, so it was nice to find a relatively inexpensive amp that worked well with it. If you want lots of detail, this is not the headphone for you. It is actually closest in concept to the AKG K-1000. Think of a circle going around your ear. The earpiece attaches only at the front, and angles out. Except for the connection at the front, it's completely open (no isolation at all). In the K-1000, this arrangement (angled driver in the open) results in strong imaging, but the F-1 just doesn't have enough detail to pull it off. Despite its flaws, I still have one. Best use I've found is actually with Headroom amp and portable DVD player, for watching movies. It's great for that.
