LFO — One Knob, Three Effects

Explore Low Frequency Oscillator (LFO) modulation effects. An LFO generates a slow waveform that modulates an audio parameter -- creating effects like tremolo (volume wobble), vibrato (pitch wobble), and filter sweeps (tone color changes).

Try the presets to hear each effect, then adjust the rate, depth, and waveform shape to explore how LFO parameters affect the sound.

One LFO, three musical effects, seen and heard at once.

Tremolo · amplitude

Presets:

How It Works

Tremolo modulates the oscillator's gain (volume), creating a pulsing effect
Vibrato modulates the oscillator's frequency (pitch), creating a wobbling effect
Filter Sweep modulates a lowpass filter's cutoff frequency, creating a wah-like tone sweep

Code Example

typescript

import { createLFO, createOscillator } from 'ez-web-audio'

const oscillator = await createOscillator({ frequency: 440, type: 'sawtooth' })

// Create an LFO at 5 Hz with sine wave
const lfo = createLFO({ frequency: 5, depth: 0.3, type: 'sine' })

// Connect to gain for tremolo effect
lfo.connect(oscillator, 'gain')

lfo.start()
oscillator.play()

// When done, stop in reverse order — LFO first, then source
lfo.stop()
lfo.disconnect()
oscillator.stop()

Cleanup

Always stop the LFO before stopping the audio source to avoid a brief gain pop:

typescript

lfo.stop()
lfo.disconnect() // Remove from all modulation targets
oscillator.stop()

For automatic cleanup tied to the sound's lifecycle, use syncLifecycle:

typescript

lfo.connect(oscillator, 'gain', { syncLifecycle: true })
// LFO stops and disconnects automatically when oscillator.stop() is called
oscillator.stop()

LFO — One Knob, Three Effects ​

How It Works ​

Code Example ​

Cleanup ​

Further Reading ​

LFO — One Knob, Three Effects

How It Works

Code Example

Cleanup

Further Reading