1st string trouble ESP HORIZON FR II + EMG

The first string sounds significantly quieter than others. Except some really unnatural attack angles. (also see another example - http://www.youtube.com/watch?v=VmlDsuOXsu8 )

I've tried different sets of strings, including Elixir. Didn't help.
I've tried to change the battery. Didn't help.
I've tried to bring the string closer to the pick-up. Didn't help.
It can't be electronics, because at some unnatural attack angles it DOES sound good.
Without plugging in all strings sound fine.

I think it's the problem either of ESP horizon design or EMG-81/60 pickups.
Too bad I didn't pay attention to this, when I was buying it :((

Видео 1st string trouble ESP HORIZON FR II + EMG канала Corsa096322