A tweeter with a third order high pass filter with a crossover frequency of 5000 Hz driven by the 100 watt amplifier used in the power chart above, will recieve about 1.6 watts at 2500 Hz versus 25 watts with a first order filter at full output. The use of higher order filters allows loudspeakers to be played at the limits of their efficiency. Different orders may be used in your design. You can have a first order low pass filter for a woofer, a third order narrow band pass filter for a mid-bass, a second order band pass filter for a midrange, and a third order high pass filter for a tweeter. When building passive crossovers, be sure to calculate for the correct impedance of each loudspeaker.
Impedance is relative to frequency.