Speaker relative efficiency/sensitivity when using a high pass filter


Is there a formula/algorithm/rule of thumb for calculating how a speaker's power requirements might change when the lower frequencies are handled by a subwoofer?  Specifically for a ported speaker with a supposed frequency response down to 35Hz and an a 89dB sensitivity with a second order crossover at 80Hz. I know it goes down but by how much? I recognize that power requirements increase as frequency decreases but is the difference enough to allow for a less powerful amp? I would think so.

 

tcutter

Showing 1 response by kraftwerkturbo

Similar but different question: with crossover (12 db/octave) at 200 Hz, how much (percentage) of the power goes to the low pass, how much to the high pass? 

Background: trying to determine (for class A or tube) what power rating for the amp I should eyeball for the high pass.