I'm looking for a headphone that's very good for classical music (neutral + big sound stage + clarity). My current setup includes a HD598 and an FX-Audio X-6 DAC and amp. Myself, being a cheap student, am struggling to justify spending the amount needed for the HD600 or the 650's (that's food for one month!). What are some somewhat cheaper alternatives that can still deliver an upgrade to the HD598's with respect to its classical performance, but are cheaper than the 600's or the 650's? Thanks in advance.