I have two access points on the same floor (the main floor) of the house because on this floor I have my office, the kitchen, and my wifes office. One AP is in her office, and one is in mine. Thus, at NO TIME while on this floor of the house, are you EVER more than 30 feet from an access point. There may be one or more walls between you an the AP, but you're never more than 30 about feet.
Yet - despite this proximity to an AP, my speed consistently drops down below 54Mbps. Very usually reaching 6Mbps or even 1Mbps according to the laptop connection status indicator (Windows and Linux both confirm the speed) or our Android phones.
The AP's are g/n, and all my wireless devices are g/n. So I should have (at miniumum) 54Mbps, which would at least be OK for watching YouTube, but 6Mbps is just not cutting it.
I have tried several different types of APs, and since they all have the same effect I am starting to believe it is either user error, or my house is a Faraday cage.