Clears bins above or below a cutoff point.
PV_BrickWall.new(buffer, wipe: 0.0)
Can range between -1 and +1.
wipe == 0 then there is no effect.
wipe > 0 then it acts like a high pass filter, clearing bins from the bottom up.
wipe < 0 then it acts like a low pass filter, clearing bins from the top down.