Lockhart Wavefolder

I’d like to share a Csound user-defined opcode port of the “Virtual Analog Model of the Lockhart Wavefolder” by Fabián Esqueda, Henri Pöntynen, Julian D. Parker and Stefan Bilbao that was presented at SMC 2017. The paper reference is:

F. Esqueda, H. Pöntynen, J. D. Parker and S. Bilbao, “Virtual Analog Model of the Lockhart Wavefolder”, in Proceedings of the 14th International Sound and Music Computing Conference (SMC-17), Espoo, Finland, July 5-8, 2017, pp. 336—342.

The authors have placed a website with the original paper, errata, and a Max/MSP/gen~ implementation at:

I have converted the gen~ code to a Csound user-defined opcode and placed the code and test file here:

The test instrument follows the recommendations of the paper to use a cascaded wavefolder structure with input gain and DC offset parameters. (See figure 9 in the paper.) The sampling rate is 88.2khz as mentioned in the paper to deal with anti-aliasing issues without having to use oversampling.

An example render of the test CSD file is below, modulating both the gain and DC offset parameters:

I’m very excited by all of the wonderful sonic possibilities! Bravo to the original authors for their work!