impedance

Hi, I have a pair of B&W 685 with the dust covers on tweeter pressed in. I found some video on Youtube on how to remove and replace the diaphragm and also found some replacements on Ebay that hopefully will fit. I've found replacements with impedance of both 4 ohm and 8 ohm, which one would fit...

Hello. I recently got an audio interface for my super basic home studio (Audient ID4 MkII). What I didn't realize is that its headphone output has quite high an impedance (22 Ohms @ 1khz), while my Shure SE535 IEMs have impedance of just 36 Ohms @ 1khz, dropping as low as 8 Ohms at some...