Memphis VIV SIXFIVE Series Instructions Manual page 15

Band pass crossover:
With the crossover switch in the "BP" setting, you can use both the low pass and high pass adjustments to create your custom band pass
filter. Use the HI-PASS adjustment to change the frequency point of the low-end slope. Use the LO-PASS adjustment to change the frequency
point of the high end slope.
This feature allows you to custom tune the sound of your mid-range speaker. You can match the size and frequency response of your mid-range
speaker to the amp allowing you to get the most out of your speakers.
Bandpass lter
LO-PASS adjustment
HI-PASS adjustment