[Andir]

You say you own a PS3, but you don't notice that most of the heat (and exhaust) is directed out the right side [according to the photos]? The side with the open grill mesh by the power button is where it vents the most. The air coming out of the side skewed the noise in favor of the 360 (as it doesn't have a vent on the bottom where you measured.)

I'm just saying that you should measure the sound of all the consoles by setting the meter directly in front of all the consoles to avoid "wind disturbance".