Hi, I'm interested in headphones (around-the-ear) for $400-600 and I was thinking about the HE-400. I mainly listen to Rock, Country & R&B and will be sourcing from my Macbook Pro. Let me know if I should choose another headphone! In addition, I'm a bit confused about amps? I have a Denon 1912 Receiver (http://usa.denon.com/us/Product/Pages/ProductDetail.aspx?CatId=StreamingMedia(DenonNA)&PId=AVR1912(DenonNA)) with a Phone Connector, can I use that to power my headphones? & What would the quality of the Denon be compare-able to? Schiit Valhala? Thanks for your time!