Thanks for the response
I think I have something say about my experience with IEMs regarding the eartips, which I am a little concerned with the foam tips that come with UM1.
When I tried out UM1, ATH CK9, SF3, they all have silicon tips on them.
The UM1 has balance sound and the bass you would expect from this kind of driver, and the sound was good. As I recalled they are in about the same league, and the CK9 sounds a little more refined (maybe slightly better), but it had very little bass, and the sound signature doesn't sound good on rock, and certain type of genre, but it was surprisingly good at string and wood instruments.
After purchasing the CK9, I read about one headfier's review about how good the Shure foam tip sounds with CK9, so I bought one.
After using those tips, I concluded that the sound was much worse than the silicon one. The sound was hollow, a bit muffled, and lacked the texture of musics. I was pretty sure there wasn't any seal problems.
Because UM1 comes with the foam tips, I'm concerned with the sound I experience with CK9 and Shure foam tips, which means I need to spend extra cash for silicon tips. Maybe they are just bad combos, I don't know.
Or is it the quality(or sound signature) I should expect from those foam tips?