Explicit Modeling of Audio Circuits with Multiple Nonlinearities for Virtual Analog Applications

Virtual Analog (VA) modeling aims at recreating the sound of analog audio gear in the digital domain. As far as white-box techniques are concerned, the class of circuits that can be emulated in real-time is still limited since circuits with multiple nonlinear elements are characterized by a very high computational cost. Wave Digital (WD) Filters have been showing to be instrumental for accomplishing white-box VA modeling. Over the past few years, new techniques have been developed for widening said class, mostly requiring iterative methods for the solution of the implicit relations among WD blocks. In this article, we present a novel method that allows us to emulate circuits with multiple (even multi-port) nonlinearities in an explicit and efficient fashion by combining vector waves and neural networks. The method is general and can be applied to explicitly solve arbitrary nonlinear circuits provided that one sufficient condition on the port resistances is met. In order to show the potentiality of our approach, we emulate the VOX V847 Wah-Wah and the Arbiter Electronics Fuzz Face pedals obtaining a notable Real-Time Ratio and paving the way toward the real-time emulation of circuits with a high number of nonlinear elements.