That is a really tricky problem with these multi-driver iems. Would be handy if there was a test where you could check phase at different frequency ranges to figure out if one of the drivers is out of phase. I really enjoy comparing all these earphones, they all have their strengths and weaknesses. Somebody mentioned how the plastic housings of as AS10 actually help with their sound and that does seem to be true, I think it adds to their warmth. I really like the sound quality of the balanced output.