These are graphs of the summation of a first order filter and 2 - 4 order Butterworth, Bessel & Linkwitz-Riley filter alignments. In each graph the low
pass & high pass functions are plotted. The summation of the filters is plotted with each of the filter outputs in polarity (observe) and with the
polarity of high pass filter output reversed. In some of the graphs the observe polarity & the reverse polarity will overlap and only one will be visible.
Use the navigation box below the graphs to quickly jump from one graph to the others for comparison.