So I have them and have been listening to them for a bit all I can say is wow! My EQ sounds a bit harsh on the treble, I may tinker with it or just do what I’m doing now and use the D1s normal preset which I believe is flat. I do have to have gain on high and the amp quite high, this is a preference thing, everything feels kind of boxy until I get to a certain volume. I do have the D3 volume down about 30 notches though, due to how much easier to drive these are.
Also why did it have 3 pairs of memory foam tips all the same size? Right now I am using the supplied tips and I do have some sonicfoams, but any memory bud recommendations would be great.
Also, the FiiO genuine check site seems to not work. I press the button but nothing happens. I am sure these are but being from amazon and their price I may just ping FiiO an email.
The only negative I have right now, and this may be recording dependent. Sometimes I would like the bass to be more present, the bass boost on my Mont Blanc adds a bit too much, I know cowon has an EG so I may play about with it. Sometimes it is perfectly present and is not too heavy on the bass like the 7hz, but there are other times where I feel like it disappears to the back too much. That being said I put on the double bass drum beast that is heaven shall burn's combat and I was stunned with how great it sounded and how I could still hear the cymbals (which sound spot on) and so on despite bass being quite present. I completely understand what you said about being very technical sounding but still musical. These are a special pair of IEMs, I think I just need to get used to BA bass compared to planar.
I have also tried it with some symphonic metal by one of my favourite bands Versailles, and despite the bass issue I mentioned, for the most part it is still very present especially on the solos and sounds absolutely fantastic, it is so smooth! What really impresses me though is all the little details I am hearing. Maybe I could hear them with my P1s but things are sticking out in a way I believe my P1s were missing, the detail retrieval on the FA7s is absolutely stunning. I love all the micro details I'm hearing with the bass, I feel the chord shaking a lot, I hear the screeching up the fretboard. My mind is quite blown.
I then tried it with a variety of tracks some like Mardelas' Eclipse to see how it deals with Marinas vocals which go from very soft and gentle all the way up to screeching falsetto highs and it sounds amazing. I also tried some acoustic Yui and my god acoustic tracks particularly stand out with these IEMs, there's a lovely warmth that isn't too warm, you feel every chord vibrate, the timbre is pretty much absolutely spot on. It almost teleports you inside (great soundstage).
I don't intend to get too technical as it is above my ability, but what I can say is everything feels smooth, timbre is extremely good which for me is extremely important, highs are great and seem to have a bit of cut off to stop the harshness. Detail retrieval is nuts, nothing is fighting with each other lows,mids and highs live in harmony 90%+ of the time. The soundstage seems fairly wide, and I know the D1 isn't as good a fit as the D3 for a pair with a soundstage like this. I am very happy with these, they sound different to the P1s which is expected given the difference in tech used, where the 7hz just sounded like a mostly inferior P1 to me. I think these will be my main pair easy, I just need to try and get a little bit more bass out of them maybe (although I feel it is a recording issue most likely).
I am writing this while listening to On and On by arch enemy and the level of balance everything has, the cymbals which usually sound very harsh do not sound that harsh at all, nothing is fighting with each other it really is quite amazing.
Overall, the only weak point I have right now, which can be fixed and may not even be their fault is the bass not being quite as present as it should be, I’m talking the tiniest bit though. However, the timbre is fantastic, lows sound fantastic, so do mids highs and trebles. A lot of things that sound quite harsh, still sound harsh but it has taken sharpness of it and made it much more pleasant. These are a great all rounder, and by that I don’t mean a jack of all trades master at none either. I think these are very masterful when it comes to timbre, balance and overall tuning. In my mind a truly great pair can be used for everything, and everything is enjoyable. Which should be the case if they are accurately reproducing the music. These definitely fit that description. I definitely do not see anything being better at this price point unless you hit maybe the £900 mark, and even then, given the masterful tuning on these I think there would be a trade off. I think these are the ultimate IEMs when a budget is not unlimited but still relatively high.
Even now as I finish of writing this smiling while listening to random tracks, the detail I am hearing in the left channel’s guitar while so much going on is absolutely nuts. FiiO have done an amazing job. Even on poorly recorded tracks where the cymbals are pretty much noise, they aren't quite noise here, it is doing it's damn hardest to fix the faults of the track and has removed so much harshness and noise.