Whoa! Thanks for the tip. The vendor included three extra pairs of tips (transparent gray outer and red inner). I just tried the non-stock medium tips and difference is night and day. Also tried the tips from a pair of Nuforce NE-600Xs and noticed a similar improvement.    I'm going to have to...

**EDIT** I swapped out the stock tips and everything changed. Settled on some tips from a pair of Nuforce NE-600Xs. BigBargainOnline even included 3 extra pairs of non-stock tips, which I should have taken as a hint. I have no doubt that these are authentic now.      Recently received a pair...