HY-Filter4 is a semi-modular type effect plugin. It contains multi-engine filter + built-in 38 effect units + 10 types of modulators + the CTRL SEQ. You can modulate parameters of the main filter, bult-in effects and modulators by using the modulation units. In addition, these are controlled by the CTRL SEQ which is a grid sequencer.

It's a subtractive type poly phonic synthesizer with midi effects and audio effects. And many of synth and audio fx parameters can be modulated. You can create wide variety of synth sound with those midi/audio fx and modulations.