I received them both and FD7 will be cooked for a while but...listening to FD7 and then to A18t which costs more than 5 times its cost makes me feel the biggest loser in this hobby. It fries the A18t in every possible way, especially with the layering, separation. Very good tuning. Bloody hell. The A18t is the biggest mistake I have ever done.I also have both FD7 and FH9.
Both of them have their merits.
They are complementary.
I really hope Fiio will produce a super iem combining all the merits of FD7 and FH9.
Another thing I liked about it is that it has higher impedance, so less sensitive to any amplifier output impedance and I can easily drive it from my desktop amp. The subbass is there and clean.
I normally keep one IEM but FH9 and FD7 are both keepers.