An Automatic Design Procedure for Low-order IIR Parametric Equalizers

Vairetti G, Sena ED, Catrysse M, Jensen SH, Moonen M, Waterschoot TV. An Automatic Design Procedure for Low-order IIR Parametric Equalizers. J Audio Eng Soc. 2018;66(11):935-952. doi:10.17743/jaes.2018.0049

@article{Vairetti2018_19870,
  author = {Vairetti, Giacomo and Sena, Enzo De and Catrysse, Michael and Jensen, Søren Holdt and Moonen, Marc and Waterschoot, Toon van},
  title = {{An Automatic Design Procedure for Low-order IIR Parametric Equalizers}},
  journal = {Journal of the Audio Engineering Society},
  volume = {66},
  number = {11},
  pages = {935--952},
  url = {https://doi.org/10.17743/jaes.2018.0049},
  doi = {10.17743/jaes.2018.0049},
  year = {2018},
  month = nov,
  publisher = {Audio Engineering Society}
}

TY  - JOUR
TI  - An Automatic Design Procedure for Low-order IIR Parametric Equalizers
AU  - Vairetti, Giacomo
AU  - Sena, Enzo De
AU  - Catrysse, Michael
AU  - Jensen, Søren Holdt
AU  - Moonen, Marc
AU  - Waterschoot, Toon van
T2  - Journal of the Audio Engineering Society
J2  - J. Audio Eng. Soc.
VL  - 66
IS  - 11
SP  - 935
EP  - 952
PY  - 2018
DA  - 2018/11/06
DO  - 10.17743/jaes.2018.0049
UR  - https://doi.org/10.17743/jaes.2018.0049
PB  - Audio Engineering Society
LA  - en
AB  - Parametric equalization of an acoustic system aims to compensate for the deviations of its response from a desired target response using parametric digital filters. An optimization procedure is presented for the automatic design of a low-order equalizer using parametric infinite impulse response (IIR) filters, specifically second-order peaking filters and first-order shelving filters. The proposed procedure minimizes the sum of square errors between the system and the target complex frequency responses instead of the commonly used difference in magnitudes, and exploits a previously unexplored orthogonality property of one particular type of parametric filter. This brings a series of advantages over the state-of-the-art procedures, such as (1) an improved mathematical tractability of the equalization problem, with the possibility of computing analytical expressions for the gradients, (2) an improved initialization of the parameters, including the global gain of the equalizer, (3) the incorporation of shelving filters in the optimization procedure, and (4) a more accentuated focus on the equalization of the more perceptually relevant frequency peaks. Examples of loudspeaker and room equalization are provided, as well as a note about extending the procedure to multipoint equalization and transfer function modeling.
ER  -