physics of a sub and moving air

[Triticum Agricolam]

We aren't talking about tuning, well I'm not. My point iss, two subs, with same x max ( or whatever you want to call it) but with different max power ratings, will each move the same distance under their respective max power.

Since both move ghe same distance, if they are both played at max volume, the higher power sub will move more air.

Or am I wrong?

Let assume we are working with a sealed box, since they make everything simpler. If you have two different subs, with the same cone area, moving the same distance, their output is going to be the same, regardless of their power rating or how much power is being put into them. With sealed box (and infinite baffle) output is directly related to the cone displacement of the sub (cone displacement is cone area multiplied by cone excursion). Generally speaking the lower RMS rated sub will probably use less power to produce the same output since lower power handing subs usually have less moving mass. Usually higher RMS rated subs have greater Xmax, which is why they have greater output potential.

With ported boxes everything is different though.