Originally Posted by WretchedExcess
Wattage used to be a good estimator of volume, back in the days when everyone wanted to use efficient speaker arrays. Now people are intentionally using inefficient speakers in small boxes and driving them with insane amounts of power to get LF extension. Now that inefficient speakers and small boxes are in the game, wattage doesn't mean what it used to mean.
Today's speakers are no less efficient than they used to be. All that's changed is that todays speakers have longer excursion, so they can take more power and you can use less of them.
OP, watts aren't a good estimate of volume, because most speakers run out of excursion long before they reach the wattage limits, but some don't, so you can have two speakers with the same wattage ratings but very different volume capabilities.