Well, I've had my HD700s for about 2 months now, and I have to say that these are some seriously wonderful headphones to my ears. I have found that a lot of people are correct in saying that these are semi-amp dependant". With some of the gear I have used to push them, I have seen some of that sibilance that is a bit harsh. I absolutely love the mids, the bass' accuracy, and the soundstage, and clarity. I just wanted to tame them a bit in the highs (for some music).
My problem is that I don't have the budget (currently), to go with some nice tube amps. All of my current equipment is portable (I suppose I could count my Yamaha reciever, but I don't find the sound that good right out of the HP jack for pretty much any HP). I have done some testing to find the right combination of portable gear that sounds best to my ear (for solid state, and for what I currently own). Some of my gear is as follows:
- Fiio X5
- Fiio X3 (2nd gen)
- Samsung Galaxy Note 4
- iPod Touch (5th gen)
- iPod Touch (3rd gen)
- Asus ROG G750JM gaming laptop
- Fiio E17 (original)
- Fiio E17K (new version)
I have tried all combinations I can think of with this equipment because, believe it or not, they all sounded different (though with some lesser HP they don't as much). I found that using the X5 directly, they sounded pretty good, but only PRETTY good (not great), and the sibilance that others have talked about are very present on some music (lots of pop, and rock where compression is present). I found it to be even worse using either the E17, or E17K, which was expected by me. The X5 is pretty bright by nature, as well as the E17 amps.
I thought to go with the iPod Touch (3rd gen) next. As you might have expected, there just was not enough power to drive these properly (volume, AND dynamics), so I added the E17 amps to the mix (one at a time of course hehe). They sounded decent out of the L cable into the different amps, but still didn't sound as good to my ears as I would have liked. The power and dynamics WERE better, but again the bright nature of the Fiio products hindered the sound overall. Using the HO of the iPod actually sounded better, but it still was not what I was looking for. I think the more "digital" sound of that model of iPod was getting the better of the sound.
I tried the X3 (2nd gen) with the Fiio amps also, but with similar results as the X5 (if just a shade less sibilant with some music). I listened without the amps at all, and found this to actually be my second favorite setup for these headphone. The X3 (2nd gen) is just less bright (overall) than the X5, with a bit more bass also. This was a decent pairing with the headphones.
The gaming laptop just sucked right out of the HP jack, but had some super soundstaging, and clarity using the E17K (the regular E17 didn't do well at all here) as the DAC/Amp. But the bass was way too weak, and could hardly be heard, although the sibilance was not present here.
By far, my favorite setup for these headphones (using my portable gear) is the iPod touch (5th gen). I know, I can hardly believe it myself. I did find it as weak as the other iPod (volume and dynamics) alone, but paired with an amp made it all come together. I have always found the iPod Touch (5th gen) to be VERY warm, and I have stopped using it altogether with my Momentums, and Momentum wireless for that very reason. In this case the warm nature what exactly what I was looking for. The E17K was not good for this, though. I found the older E17 to be perfect for it. I find there to be PLENTY of bass impact, trebles never get sibilant (except if I throw low quality music at it), and the mids are just brilliant.
Now, I'm not saying that this is the best, or even ideal in the setup, but I find that I can simply listen for hours on end to music and never seem to get tired of it. BTW all of the music I listened to was lossless, and I used the same set of songs across all devices. I tried to make it as fair to my ears as I could.
Thanks for reading my (very) longwinded ramblings. Cheers!