Digital filters are used in audio systems for attenuating or boosting the energy content of a sound wave at specific frequencies. The most common filter forms are high-pass, low-pass, band-pass and notch. Any of these filters can be implemented in two ways. These are the Finite Impulse Response (FIR) filter and the Infinite Impulse Response (IIR) filter, and they constitute building blocks to more complicated filtering algorithms like parametric equalizers and graphic equalizers.
