I've had my SRH 840's for almost 2 years and they're definitely the best headphones I've ever owned. They've pretty much been plugged into my Focusrite 2i2 at all times since I bought them just for convenience. What I'm wondering is, can I make them sound that much better if I bought some kind...

I plug them into a focusrite 2i2 at the moment. 

I've had a pair of SRH840's for about 2 years and I love how they sound, however they do get uncomfortable after long periods of listening and are lacking a bit in the bass department. I'm looking for a new pair of headphones under $400 that are closed back and I'd prefer to not have to buy an...