It seems the impedance on the HF5 is a bit too low for my Sansa e280 portable player. The volume is fairly loud even on the lowest setting. Has anyone tried using the HF5 with the ER4P/ER4S adapter? I assume the added impedance would lower the volume at a given player setting.

I'm looking for some IEMs with maximum isolation. I have very sensitive hearing and work in a noisy office. For me, sound quality is a distant second behind maximum isolation. Price range is $200 and under. Based on my research, it looks like the Etymotic er4 and hf5 provide the most...