Ok, so it turn out it's my Emotiva XPA3 is the one causing the problem. I use the other speaker to test and it came out with the same distortion. Switched the power channel that used to power my center to power that left speaker, everything were OK!

wasting my time taking off the tweeter, swapped them, run test, bringing down the other speakers from my living room, sweating like hell and it's the amp problem!