The niveau filter and its software emulation have their origin in our creative compressor, the mpressor; adding interesting tonal variations after the compression stage. The effect of this filter is unique and powerful, while its operating is really easy:
Just choose the desired center frequency, then turn the gain controller clockwise to cut the low frequencies and boost the treble at the same time. Or, when you turn the controller counter-clockwise, the effect will be just the other way round.
Extreme settings of the gain controller provide further flexibility: While the fully counter-clockwise position will result in a low pass filter, the fully clockwise setting will give you a high pass filter instead.