Filter

A module that reduced or removes certain frequencies and harmonics from the sound that is passed through it. In a synthesizer, the most typical filter types are low pass (passes all of the harmonics below its cutoff or corner frequency untouched, and then reduces the level of higher harmonics the further you go above that cutoff frequency), high pass (passes all harmonics above its cutoff frequency untouched, and reduces the level of progressively lower harmonics below the cutoff), bandpass (harmonics right around the cutoff are passed intact, and then reduced more in level the further away they are above or below the cutoff frequency), and notch (harmonics right around the cutoff frequency are reduced or cut out entirely; others above or below are allowed to live).