A fixed-frequency set of notch filters and bandpass filters, arranged such that they reproduce the chracteristics of a naturally resonant object or space, such as a violin body, a drum head, or the human voice tract. Formants are responsible for the particular timbral character of many sounds in nature; in particular, the strong set of formants created by the human mouth and vocal tract is what creates the distinct sounds of the human voice.Specialized formant filter banks are designed to emulate this by providing a set of very narrow-band notch filters which can be set up in a desired relationship. Since the formants do not track with the pitch of the sound being processed, they result in a tonal character that varies with the pitch.The presence of strong formants in a sound presents a problem for pitch shifters, which cannot easily hold the formants fixed while changing the pitch, but the newest generation of pitch shifters has at least partially overcome this problem. See also munchkinization.
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