low-pass filter

A low-pass filter is a filter that lets only frequencies lower than its cutoff frequency pass, letting bass through while cutting treble¹. In effects pedals it is used to darken or soften tone: it can chop treble from delay repeats², add darkness to repeats that hints at BBD delay sounds³, or generate warm, ringy tones reminiscent of vintage synthesizers⁴. Dedicated low-pass filter pedals can simulate the high frequency roll-off of speaker cabinets or, at extreme settings, turn a bass guitar signal into a low end dub tone⁵. Some designs use a brick-wall low-pass filter, cutting off at 2.6 kHz, to give loops the character of a damaged cassette⁶.