Bandpass Filter

A bandpass filter combines the actions of a highpass and a lowpass, letting through only a band of frequencies centered on the cutoff and rejecting content on either side. The width of that band is set by resonance or a bandwidth control — narrow settings isolate a thin, focused slice of the spectrum, while wider settings pass more of the sound. Bandpass filtering produces a characteristic thin, nasal, telephone-like quality that is great for lo-fi effects, radio voices, and honky, mid-focused tones. Sweeping a resonant bandpass across the spectrum creates vocal, wah-like movement, and it is a common way to carve rhythmic, formant-like textures out of otherwise static pads and noise sources.