I am using a V-Sonic GR04 classic edition, it's the first over-the-ear style IEM I got. Anyway, when I'm using the IEM, sometimes when I turn my head, the sound will change, or worse, one side of the IEM will sound more quiet.  Is this a fit issue? or a problem with the IEM itself?   Thanks

Long story short, I tried a UE TF10, Panasonic HJE900 and Phonak PFE121 last time, output from my HTC Explorer. This is my first time trying audiophile item, and TBH I can't tell much difference from my cheap Philips, I didn't notice all the goodies people talking about, like the soundstage. Now...