Virtual Analog Model of the Lockhart and Serge Wave Folders

Fabian Esqueda, Henri Pontynen, Julian Parker, Stefan Bilbao

Research output: Contribution to journalArticlepeer-review


Wavefolders are a particular class of nonlinear waveshaping circuits, and a staple of the “West Coast” tradition of analog sound synthesis. In this paper, we present analyses of two popular wavefolding circuits—the Lockhart and Serge wavefolders—and show that they achieve a very similar audio effect. We digitally model the input–output relationship of both circuits using the Lambert-W function, and examine their time- and frequency-domain behavior. To ameliorate the issue of aliasing distortion introduced by the nonlinear nature of wavefolding, we propose the use of the first-order antiderivative method. This method allows us to implement the proposed digital models in real-time without having to resort to high oversampling factors. The practical synthesis usage of both circuits is discussed by considering the case of multiple wavefolder stages arranged in series.
Original languageEnglish
Number of pages23
JournalApplied Sciences
Issue number12
Publication statusPublished - 20 Dec 2017


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