Ben Holmes

Ben Holmes

Audio Hardware Engineer

Publications

Comparison of Germanium Bipolar Junction Transistor Models for Real-Time Circuit Simulation

Published in Proceedings of the 20th International Conference on Digital Audio Effects, Edinburgh, Scotland, 2017

The Ebers-Moll model has been widely used to represent Bipolar Junction Transistors (BJTs) in Virtual Analogue (VA) circuits. An investigation into the validity of this model is presented in which the Ebers-Moll model is compared to BJT models of higher complexity, introducing the Gummel-Poon model to the VA field.

Recommended citation: B. Holmes, M. Holters, M. van Walstijn. "Comparison of Germanium Bipolar Junction Transistor Models for Real-Time Circuit Simulation", Proceedings of the 20th International Conference on Digital Audio Effects, Edinburgh, Scotland, Sept. 2017

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Physical model parameter optimisation for calibrated emulation of the Dallas Rangemaster Treble Booster guitar pedal

Published in Proceedings of the 19th International Conference on Digital Audio Effects, Brno, Czech Republic, 2016

In this work we explore optimising parameters of a physical circuit model relative to input/output measurements, using the Dallas Rangemaster Treble Booster as a case study.

Recommended citation: B. Holmes and M. van Walstijn. "Physical model parameter optimisation for calibrated emulation of the Dallas Rangemaster Treble Booster guitar pedal", Proceedings of the 19th International Conference on Digital Audio Effects, Brno, Czech Republic, Sept. 2016

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Improving the robustness of the iterative solver in state-space modelling of guitar distortion circuitry

Published in Proceedings of the 18th International Conference on Digital Audio Effects, Trondheim, Norway, 2015

Two methods are presented which attempt to reduce the expense of iterative solvers. This is achieved by applying information that is derived from the specific form of the nonlinearity.

Recommended citation: B. Holmes and M. van Walstijn. "Improving the robustness of the iterative solver in state-space modelling of guitar distortion circuitry", Proceedings of the 18th International Conference on Digital Audio Effects, Trondheim, Norway, Dec. 2015.

Download paper here