ABSTRACT
Filters are used in a wide range of audio processes to shape spectral envelopes. At the simplest level, filters are characterised by the amount of attenuation that they apply at particular frequencies. This enables a signal path to relate primarily to a restricted band (or bands) of frequencies. This is useful for tonal shaping because changing gain makes it possible to emphasise or deemphasise particular frequency ranges. It is also useful to isolate a range such that the signal reaching a subsequent process block is targeted on a certain area of the frequency spectrum.
