Those two aren't really for percussion, though...instead, that pair of 4 hp modules are ones I selected so that you can have massive, slab-cracking BASS. The two slightly detuned VCOs plus that suboscillator will have the capability of generating POUNDING low-end. Also, when you're dealing with that sort of bass sound, you want simpler waveforms which will have more kinetic energy at their fundamentals. Think "Miami bass", but taken to a more violent level.