Lowpass Filter

The lowpass filter is the most commonly used filter in synthesis. It allows frequencies below the cutoff to pass through unchanged while rolling off those above it, so lowering the cutoff removes brightness and makes a sound progressively darker and warmer. This mirrors how sound behaves in the real world, where distance and obstacles naturally muffle high frequencies, which is part of why lowpass filtering sounds so musical. Sweeping the cutoff with an envelope or LFO creates the iconic filter sweeps and wobbles heard throughout electronic music. Combined with resonance, which emphasizes frequencies right at the cutoff, the lowpass filter is the heart of subtractive synthesis and the tool you reach for most when shaping a sound's tone.