As a knowledgable tennis fan (unlike some people here), I can tell you exactly that. There are tennis players who have problems with playing indoor tennis because of the different lights, different sounds etc. compared to outdoors and Nadal is obvioulsy one of those players.
So Rafa has bad eyes and ears? I wonder why Toni isn't saying this. Different sounds, you have got to be shitting me. Have you fucking played on a tennis court in your life? Rafa is the one making the sounds regardless, so what the fuck do different sounds have to do with this? His grunt is too loud for himself? Artificial lighting can be a problem, but unless Rafa had implanted robotic eyes only for the last few games of Wimbledon 2008, then your argument makes zero sense. What a fucking joke..
So I'm guessing Cincinnati has bad lights and bad sounds, right? He has never made a final there. Miami must have bad lighting and sounds as well, he has yet to win there. In fact, most non-clay events must have bad lighting and sounds, only Indian Wells, Wimbledon and Canada must have good lights and sounds, those are the only events he has won more than once.