I have a Minidsp on order to use as a digital crossover, my Audio Physic Sitara 25 speakers are ported (89db / 36 Hz specification). I use with stereo subwoofers and Vincent SA31MK / SP331MK amplification. I want to reduce the load on the power amp and speakers as the Vincent is class A for the first 10 watts. (Not sure if that means into 8 ohms ? as AP's are 4 ohm load then could be 10 watts or maybe 20 watts?). I will be experimenting and will add my experiences to this page.
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.