No! It is a common misconception. I often hear people talk about how a 50 watt Marshall is more appropriate for most people, since it's half the wattage. Really? It sure isn't half as loud!
The perceived volume difference between 50 and 100 watts is actually very small.
And that, ladies and gentlemen, is how this decibel/loudness/wattage thing works.
Enjoy your loud amp(s)!!