I have a 5th Gen AirPort Extreme sitting on top of my A/V cabinet. My wife wants it hidden. I was thing of placing it vertically behind the A/V cabinet. My question is will this placement affect the wifi signal?
It might. If the cabinet is full of receivers and DVRs and such that all put off electrical interference, it could impact your wit signal. Hard to say how much without just trying it out. If you have a relatively small home and the wifi coverage is strong now, a slight degradation like this may not even matter.