Filters are one of the key elements in the sound of any synthesizer. The use of synthesizer filters is not only to control sound but they can also add character to recorded acoustic- instrument tracks. A filter acts as a signal processor. When input is fed into the system, it may be from the oscillators of the synthesizer, or a recorded track or even a live music and it automatically changes the signal in some way. To be more specific, a synthesizer filter changes the frequency contour of a signal.

In the earlier days, filters characterized the sound of the synthesizers more than anything else. Now, with the advancement of technology, much-expanded sound capacity models, the use of filters may have reduced a little, but it is still a key element in sound design.

Synthesizers filters can be described by how they have an effect on different parts of the frequency spectrum. These filters are of different kinds with respect to their controls of frequencies. A Lowpass filter reduces the level of higher frequencies while leaving lower frequencies unchanged. This is similar to that of the treble control on your stereo. A highpass filters do the opposite. A bandpass and band-reject filters reduce the level of frequencies inside or outside of a frequency band. Lowpass filters are the most common kind of filters.

A synthesizer filter can be switchable among the above-mentioned modes of filters, which includes the Lowpass filters, highpass filters, and a bandpass and band rejects filters. There can also be several other types of filters to be arranged in series, to operate it successively or to arrange parallel to operate it simultaneously.

The prize of a synthesizer can vary from another one depending on the distinctive sound of their filters. The synthesizer filter is one of the key elements in the sound of any synthesizer.

In case of a digital synthesizer filter it will not only enable you to set the frequency but also enable you to set the waveform, number of channels, and other properties through the property page. They enable you to vary the basic waveforms to some extent and smooth out the edges of the original waveform. Take for instance, if you listen to a sawtooth wave, you will find it rather harsh this is because the waveform has a lot of sharp edges. These edges are in the acoustic terminology called overtones and they can be removed by applying a filter to a waveform.

Synthesizer filter effect varies with the pitch of the sound being filtered. And there is a setting called keyboard tracking or pitch tracking to perform this job. It can determine how much the filter cutoff frequency is affected by the pitches being played. The keyboard tracking range can vary from 0 to 2, which means no tracking or cutoff increased to twice as fast as the pitch respectively.

There is an endless list of what synthesizer filters can do. There are no limitations as to what they can perform to produce a better sound. They have the abilities to remove parts of the audio spectrum and create new tones from the old.