I've just spent a couple of hours comparing the IE800, FI-BA-SS and K3003. Make no mistake, these are all very impressive earphones that reproduce sound of remarkable quality.
Some brief impressions - I was aware of how small the IE800 and FI-BA-SS are but they are surprisingly tiny in the flesh. The IE800 looks like it would fit elfin like ears easily. The K3003 is considerably larger and heavier.
The clarity and detail of the FI-BA-SS is astonishing. It's a compelling listening experience to hear music you're familiar with laid bare. "Unforgiving" is an apt description of this highly resolving earphone. Listening to the IE800 was like coming home in a way. It reminded me of a honed version of my IE8. It sounded clearer and the bass had been reigned in but it was the least controlled of the three. The K3003's bass sounded more defined and better balanced in the overall mix. The FI-BA-SS lacked the bass extension of the other two but the textural detail is unsurpassed.
The K3003 combined excellent clarity, detail extraction and had good extension at both ends of the frequency spectrum. The mids were lovely with a touch of lushness and were neither too forward or recessed. The IE800's mids sounded more distant to me. The FI-BA-SS' mids were possibly even more forward than the K3003's but I'm not certain about that.
I was amazed by how dynamic the FI-BA-SS sounded but came to appreciate the more forgiving K3003 when I'd switch back to it. There were times that I thought the K3003 had more tonal weight than the FI-BA-SS, which was also welcome.
I've had the least to say about the IE800 and that's probably because it sounded like a more evolved IE8, whereas the other two were new to me. I don't want to give the impression that the IE800 is not as worthy of consideration as the other two phones because it most definitely is. I could see myself happily owning any one of these and ideally all three.
Edited by Finn78 - 1/7/13 at 3:48am