This chapter deals with some more advanced topics that may be useful to start designing Rack modules. While in the emulation of physical objects a physical law can be employed to derive the parameters, in a modular synthesis setting these can be left for maximum freedom. The exciter of the system can be created outside the module, using other techniques that may emulate a bow friction or a sharp hit with multiple bounces. If the modulation input is active, its signal modulates the resonator output. It is worth mentioning that if a constant value is sent to the modulation input, it acts as a gain. The discontinuities that are created in the input signal at the reaching of a threshold value are determinant in the bandwidth expansion of the original signal. The wavefolder will have two knobs, to adjust gain and offset. Two input ports will be associated to these two parameters, allowing control voltage signals to control them.