Just received my HE-400's, which I will be pairing up with my Fiio E17 amp/dac. I've tested the headphones on several songs / movies. I've been listening to a lot of classical and house music. What should I listen for? I have a pair of iPod earphones, and when I plug them into the Fiio E17, the mids seem to sound better. My ears may just be naive. A little bit of training / experience will change that. With the HE-400's, I can tell that the bass is awesome. Anything else I should hear out for? It's like wine tasting. You need to know what to look out for before you can judge.