With a 13 x 13 room and Pi 4's the question isn't going to be the number of db's. With very little amplification you won't be staying in the room. These speakers are HIGH EFFICIENCY so it doesn't take a lot of watts to fill a room at all.

The different components used (eg. can use Emminence, JBL, or figure your own out) tends to be related to quality, not volume so much. With the JBL components in PI 4's, or high end Emminence these are officially loud, and great sounding.

The adventure begins. Good luck.

Grant.