Gray-Box Modeling of Guitar Amplifiers

Eichas F, Zölzer U. Gray-Box Modeling of Guitar Amplifiers. J Audio Eng Soc. 2018;66(12):1006-1015. doi:10.17743/jaes.2018.0052

@article{Eichas2018_19874,
  author = {Eichas, Felix and Zölzer, Udo},
  title = {{Gray-Box Modeling of Guitar Amplifiers}},
  journal = {Journal of the Audio Engineering Society},
  volume = {66},
  number = {12},
  pages = {1006--1015},
  year = {2018},
  month = dec,
  publisher = {Audio Engineering Society},
  doi = {10.17743/jaes.2018.0052},
  url = {https://doi.org/10.17743/jaes.2018.0052}
}

TY  - JOUR
TI  - Gray-Box Modeling of Guitar Amplifiers
AU  - Eichas, Felix
AU  - Zölzer, Udo
T2  - Journal of the Audio Engineering Society
J2  - J. Audio Eng. Soc.
VL  - 66
IS  - 12
SP  - 1006
EP  - 1015
PY  - 2018
DA  - 2018/12/06
DO  - 10.17743/jaes.2018.0052
UR  - https://doi.org/10.17743/jaes.2018.0052
PB  - Audio Engineering Society
LA  - en
AB  - Musical distortion circuits, especially guitar amplifiers, have been the subject of virtual analog modeling for years. There exists two main modeling approaches: white-box modeling, where the internal properties are fully known, and gray-box modeling, where only the input and output are available. This work proposes a gray-box modeling approach for analog guitar amplifiers using iterative optimization to adjust the parameters of a block-based model. The only assumption made about the reference system is its basic structure. The digital model is an extended Wiener–Hammerstein model consisting of a linear time-invariant (LTI) block, a nonlinear block with a nonlinear mapping function, and another LTI block connected in series. The model is adapted in two steps: first the filters are measured, and then the parameters for the nonlinear part of the digital model are optimized with the Levenberg–Marquardt method to minimize a cost-function describing the error between the digital model and the analog reference system. A small number of guitar amplifiers were modeled, the adapted model was evaluated with objective scores, and a listening test was performed to rate its quality.
ER  -