Waves OneKnob Filter (ESD); filter plugin; creates smooth filter sweeps on loops, vocals, instruments, or full mixes; 12 dB/octave lowpass filter with analog, silky sound character; cutoff frequency range from below 20 Hz to above 20 kHz; resonance switch with four stages - from neutral to extreme; no quantized steps - continuous frequency sweeps possible; ideal for dance productions, breakdowns, and live DJ setups; adds organic tonal movement to vocals and instruments; automatable for wah-like effects and dynamic transitions; true stereo processing - no mono summing with fake stereo; simple one-knob design for fast workflow