Well, what can I say. With the sole exception of bass impact and presence, down to the lowest octave, the Primes are just out-classed by the HD 800 S.
The funny thing is, I appreciate the Primes even more! What they do, for a closed can, is amazing. I might give them up in favor of the Ether C, but they are a pretty good compliment for the 800 S's. In fact, they have some similar traits, especially with drums and guitar. But the treble on the 800 S's seems somehow smoother, with not even a hint of grain. Also, male voices and vocals on the Primes seem slightly congested, almost "chesty".
In terms of soundstage- it's no contest. This is really apparent on movies and TV shows. But the Primes are not embarrassed. It's just that things seem more closed in to the center, which makes sense. But actual imaging, the placement of instruments, the position of actors, seem much more realistic on the 800 S's. With speakers, I find that's the result of substantial room treatment and speaker placement, along with some judicious EQ. With the 800 S, I think it's the tolerance of the drivers and how well-matched they are, along with the slight slant and position of the drivers, which they claim is more like regular speakers
I ran both balanced on my Liquid Carbon, fed by the Benchmark DAC. The results seemed exactly what I expected, but again, the Primes are no slouch in any area. I'm still quite proud to have them, being upgraded Alpha Dogs and all. They have more "weight" overall, but that is at the expense of fine detail.
I guess the Sennheisers remind me of great speakers, whereas the Primes are simply great headphones. It's just a different experience: but both are really good!
