Sounds like a grounding issue maybe, does the headphone plug fit all the way into the jack in the front? If so re-seat your audio header and make sure its on the right pins.
I think I know what's the problem .. dusts.. I open my side panel ( where my audio jack is at ) and saw quite some dust there , cleaned it and now it works fine .
They're mostly the same thing.
Ah , okay , I didnt know that , thanks .
Does the IEM have a microphone? The front jack might not like that and is causing some problems.
Nope , but my problem is fixed , for now , probably caused by my laziness ..