The M-stage pairs incredibly well with the HD 700; it blows away the Fiio E9 (one of my first headphone amps), which accentuates the treble and robs the HD 700 of its surprisingly robust character. I think the HD700 appreciates the M-stage’s extra horsepower; with the gain set to max, the bass is just sublime and oh-so clean. Comparing the HD 700 to the HD 800, I was surprised to discover that the HD 700 produces a much punchier bass response, while maintaining its crystal clear, grain-free character. The HD 800, on the other hand, reaches down deep into the sub-bass, extracting an amazing amount of detail from that region (man, the HD 800 is just unreal when it comes to detail retrieval!) The Matrix also improves the HD 700’s sound-stage; the Fiio E9 sort of robbed the HD 700 of its sense of space. The HD700’s soundstage, though, is not dramatically wide like the k701, but rather surprisingly balanced and symmetrical. I love this. With all that said, the HD 700’s upper end sounds a little “smoother” through my Little Dot Mk3 tube amp; the tubes subdue the treble just enough to make you forget about the treble. The difference between the MK3 and the Matrix on that score is subtle but notable. Unfortunately, no amp can help rectify the HD 700’s upper mid-range dip, and I’m now committed to adjusting the offending frequencies with my graphic equalizer. This, for me, is a very small complaint but for some folks the upper mid-range dip may be a deal breaker, and the Matrix won’t resolve this problem. Hope this was helpful. Cheers.
