Filter Cutoff

Cutoff frequency is the single most important filter parameter. In a lowpass filter, frequencies above the cutoff are progressively reduced — a low cutoff creates dark, muffled sounds while a high cutoff lets the full brightness through. In a highpass filter, frequencies below the cutoff are removed. The cutoff frequency is typically measured in Hz and can range from 20 Hz to 20,000 Hz. Modulating cutoff with an envelope creates the classic filter sweep heard in countless electronic tracks. The relationship between cutoff and resonance defines the filter's character — high resonance at the cutoff frequency creates the signature squelchy acid sound of the Roland TB-303.