Not sure if I'm wording my question correctly but does anyone know if you can combine line-in devices for something like an iPhone?   For example, if I get a Fiio E1 and my IEM's have a built in mic. will the both work?   How about with the iLuv IEA15?

Hello Head-Fi. I currently own a pair of Sennheiser CX 680's. I've been quite happy with them since day one on all fronts (sound, build quality, looks, fit, etc.) but after lurking around here and reading about burning in for larger headphones I decided to experiment on my 680's. My newbie way...