AES San Francisco 2010
Tutorial T7

Friday, November 5, 10:15 am — 11:15 am (Room 120)

T7 - Analysis and Modeling of the dbx 902 De-esser

Aaron Wishnick

Analog device modeling is an increasingly important tool in modern audio signal processing. There are a variety of techniques for modeling many different devices. Here we will present an example of modeling one device, the dbx 902 de-esser, a very well regarded hardware de-esser, from start to finish. We will describe a set of techniques for analyzing the hardware unit as a “grey” box to determine its characteristics, incorporating the device’s specifications, and, most importantly, empirical results from probing the unit with test signals. Mathematical models for analyzing the de-esser will be presented, which would also apply to other dynamic range control processors. We will examine how this device differs from other typical implementations of de-essers, and finally, describe a digital emulation. The lessons learned here should be useful to any beginner interested in device modeling.

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