Learn Audio Electronics with Arduino

Chapter 8

Audio filters

This chapter will introduce first-order audio filters, component networks that vary their amplitude output based on the frequency of the input signal. To help explain the need for audio filters, the chapter begins with a discussion on the frequency-dependent nature of human hearing – audio circuits have to shape the level of certain audio frequencies with filters to compensate for their relative perceived volume by the human ear. The chapter will also introduce Bode plots that show both the frequency response and phase of a signal – these plots are a fundamental part of audio circuit design and we will use LTspice to create them. The chapter then covers basic filter characteristics like cutoff and slope and how they ...