Audio filter
An
audio filter is a type of
filter used for processing
sound signals. Many types of filters exist for applications including
graphic equalizers,
synthesizers,
sound effects,
CD players and
virtual reality systems.
In its simplest form, an
audio filter is typically designed to pass some frequency regions through
unattenuated while significantly attenuating others. In some applications, such as in the
design of
graphic equalizers or CD players, the filters are designed according to a set of objective criteria such as
pass band, pass band attenuation, stop band, and stop band attenuation, where the pass bands are the
frequency ranges for which audio is attenuated less than a specified maximum, and the stop bands are the frequency ranges for which the audio must be attenuated by a specified minimum.
In more complex cases, an audio filter can provide a
feedback loop, which introduces
resonance (ringing) alongside attenuation. Audio filters can also be designed to provide gain (boost) as well as attenuation.
In other applications, such as with synthesizers or sound effects, the aesthetic of the filter must be evaluated subjectively.
Audio filters can be implemented in analog circuitry as
analog filters or in
DSP code or computer
software as
digital filters.
Non-linear filters are also used in audio applications: for example,
compressors,
fuzz boxes,
ring modulators.
Generically, the term 'audio filter' can be applied to mean anything which changes the
timbre,
harmonic content,
pitch or
waveform of an audio signal.
*
Software Analog Filter emulators by musicrow*
Audio crossover*
Electronic filter*
Equalization filter
