Both seem great. Both gaining popularity quickly. Isolation aside, based on reviews I've seen both have a lot offer and is difficult to decide between the two. These are some of the things I think I know but would like conformation to make sure I'm right;
Bass: Both similar, Mad Dog slightly ahead in terms of sub bass.
Mids: Both are orthos so I assume both are fantastic in the mid range. The HE-400 being a bit better due to being open backed.
Isolation: Obviously one offers privacy and the other is a boombox in comparison.
Soundstage: HE-400 I would assume is in another league due to being open backed.
Instrument Seperation: I would guess because of its superior sound stage the HE-400 wins here as well.
These are the things I need help with;
Treble: The HE-400 I heard has a little sparkle in the treble, but is otherwise laid back. I have no Idea how the mad dogs compare.
Bass Extention: Which has better bass extension?
Treble Extention: Which has better treble extension?
Efficiency: I know the HE-400 can be driven well with the magni/modi, but can the mad dogs be as well?
Sound Signiture: The HE-400 has been described as a dark headphone. Would you say the mad dog is the same?
Instrument Seperation: How do mad dogs compare to HE-400?
Speed: Which is the quicker sounding?
Generes: Both are good with a wide range of music, but what would you say each headphone works best with?
Soundstage: Despite their closed design, can the mad dogs be considered good with orchestral music too?
*** And finally, which do you prefer and why? The more opinions the better!
Any help would be appreciated!