TY - JOUR
T1 - An automatic design procedure for low-order IIR parametric equalizers
AU - Vairetti, Giacomo
AU - De Sena, Enzo
AU - Catrysse, Michael
AU - Jensen, Søren Holdt
AU - Moonen, Marc
AU - Van Waterschoot, Toon
PY - 2018/11/1
Y1 - 2018/11/1
N2 - 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 (SSE) 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 an improved mathematical tractability of the equalization problem, with the possibility of computing analytical expressions for the gradients, an improved initialization of the parameters, including the global gain of the equalizer, the incorporation of shelving filters in the optimization procedure, and 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 multi-point equalization and transfer function modeling.
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 (SSE) 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 an improved mathematical tractability of the equalization problem, with the possibility of computing analytical expressions for the gradients, an improved initialization of the parameters, including the global gain of the equalizer, the incorporation of shelving filters in the optimization procedure, and 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 multi-point equalization and transfer function modeling.
UR - http://www.scopus.com/inward/record.url?scp=85056857598&partnerID=8YFLogxK
U2 - 10.17743/jaes.2018.0049
DO - 10.17743/jaes.2018.0049
M3 - Journal article
AN - SCOPUS:85056857598
SN - 1549-4950
VL - 66
SP - 935
EP - 952
JO - AES: Journal of the Audio Engineering Society
JF - AES: Journal of the Audio Engineering Society
IS - 11
ER -