@tcutter , if you take the bass out of a speaker with any high pass filter you increase the headroom of the amplifier driving the speaker but you do not change the efficiency of the speaker one iota, it remains exactly the same. Depending on where the crossover is in the speaker you may lower distortion at some frequencies. With a full range loudspeaker this can make a very noticeable reduction in distortion at moderate to high volumes certainly over 80 dB.
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.