Mastering Modulation: A Deep Dive Into the Low Frequency Oscillator in Music Production

Feb 1

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Low Frequency Oscillators (LFOs) are pivotal for creating dynamic audio effects in music production. Functioning below our audible range, these tools, also known as low frequency oscillator, modulate other sound parameters - not to make sounds themselves, but to infuse tracks with rhythm, depth, and character.

Let's understand something more

Key Takeaways

  • Low Frequency Oscillators (LFOs) function below the human hearing threshold to modulate various sound parameters such as pitch, volume, and timbre, differentiating it from audio oscillators that create audible sound.

  • LFOs have key parameters including wave shapes, rate, and depth, which, when manipulated, can produce a vast array of modulation effects, from subtle nuances to pronounced transformations.

  • The creative applications of LFOs extend to evolving soundscapes, rhythmic patterns, and stereo movement, enhancing depth and dimension in music production across various genres and styles.

Understanding Low Frequency Oscillators (LFOs)

An illustration of a low frequency oscillator modulating synth parameters - lfo modulates many synth parameters

Dynamic sound modulation is primarily steered by the Low Frequency Oscillator (LFO).

LFOs are unique oscillators that operate at frequencies below the threshold of human hearing, typically below 20Hz. They serve a critical role in music synthesis, enriching the sonic landscape by adding movement and complexity.

However, the magic of LFOs doesn’t end there.

They set themselves apart from their counterpart, the audio oscillator, which is designed to produce sounds within the human hearing range. So, how exactly do these LFOs function, and how do they differ from audio oscillators?

Let’s explore.

the low frequency oscillator in retrologue

What is an LFO?

Operating at low frequencies, the Low Frequency Oscillator (LFO) generates waveforms for sound synthesis and modulation through low frequency oscillation.

Its name directly reflects its function in signal processing. But what sets it apart from other oscillators?

It’s all in the frequency. LFOs operate at a very low frequency, typically below 20Hz, which is outside the human hearing threshold. This is their defining characteristic.

While audio oscillators produce sounds we can hear, LFOs work behind the scenes, modulating various sound characteristics to create dynamic effects such as rhythmic pulses and sweeps, using a low frequency signal.

The LFO is like the invisible puppet master, controlling the movements of the puppet (the sound) to produce a captivating performance.

By modulating parameters like volume, pitch, and filter cutoff frequency, LFOs bring your sounds to life, introducing movement where there is static, and variation where there is monotony.

The LFO is truly the unsung hero of dynamic sound design.

A synth oscillator: multiple parameters on an audio oscillator

LFO vs Audio Oscillator

Having established what an LFO is, it’s time to distinguish it from an audio oscillator.

An audio oscillator is the sound generator in music production. It churns out repeating waveforms that, when altered and shaped, become the diverse sounds you hear in music.

On the other hand, LFOs control the movement and modulation of these sounds. They are responsible for the dynamic alterations in pitch, volume, or timbre that add depth and complexity to your music.

While audio oscillators are the architects of sound, building the fundamental structures that we perceive as music, LFOs are the decorators, filling those structures with color, texture, and dynamism.

It’s the interplay between these two types of oscillators that makes music synthesis so rich and captivating.

A photo of different wave shapes for LFO signals

LFO Parameters: The Building Blocks for Modulation

Understanding the key parameters of LFOs - wave shapes, rate, and depth - is fundamental to mastering modulation.

These parameters are like the artist’s tools, each contributing to the final masterpiece in its unique way. The wave shapes define the rhythm and character of the modulation, the rate controls the speed, and the depth determines the intensity.

By manipulating these parameters, you can create an infinite variety of modulation effects, from subtle shifts to dramatic transformations.

And now, let's examine each of these parameters in more detail.

lfo typically uses synth sound waveforms like the triangle wave

Wave Shapes

Wave shapes are the fundamental building blocks of any LFO signal. They define the rhythm and character of the modulation. The most common wave shapes generated by LFOs are:

  • Sine

  • Square

  • Sawtooth

  • Triangle

Each wave shape has a distinct influence on sound modulation, leading to a wide range of sonic possibilities.

Different wave shapes have different impacts on modulation. In the context of a modulation matrix, here are a few examples:

  • A sine wave results in smooth and gentle modulations, ideal for creating a balanced modulation effect.

  • A square wave results in distinct on/off modulation, perfect for maximizing the intensity of the effect.
  • The sawtooth wave generates a progressively dynamic and vibrant sound when applied to modulate a filter.
And, finally the Triangle wave,  produces a softer and smoother sound, often used in creating subtle changes in pitch or volume.
Understanding these wave shapes and their impact on modulation is key to mastering the power of LFOs.

Rate and Depth

Rate and depth are two other vital parameters of an LFO.

The rate parameter controls the frequency of the oscillation. It directly influences the speed of modulation, with faster rates producing rapid effects and slower rates leading to more gradual changes in the sound. Slower rates, for instance, can be used to create a slow, sweeping effect, while faster rates can create a rapid, pulsating effect.

On the other hand, the depth parameter regulates the intensity of the modulation effect. Increasing the depth leads to a more conspicuous modulation effect while reducing it produces a more subdued modulation influence.

By adjusting the rate and depth, you can fine-tune the intensity and speed of your modulation effects, giving you precise control over the sound’s characteristics. This precise control can be achieved through audio rate modulation techniques.

low frequency oscillation in retrologue

Routing Options

Routing options offer a whole new layer of flexibility and precision in controlling LFOs. They determine which parameters the LFO modulates, opening up a world of complex and evolving sounds. Some synthesizers offer a wide range of routing options, including:

  • Modulating different waveforms

  • Rate control

  • Tempo sync

  • Modulation amount applied to the target parameter

These options allow you to create unique and dynamic sounds with your synthesizer.

The ability to route the LFO signal to multiple parameters or utilize external modules opens up a world of sonic possibilities.

Imagine being able to modulate the filter cutoff, volume, and pitch simultaneously, resulting in a sound that’s constantly evolving and shifting, never static.

This is the power of routing options in LFOs 🔥.

An illustration of LFOs creating stereo panning and movement

Creative Applications of LFOs in Music Production

Having explored the mechanics of LFOs and their parameters, it’s time to examine their creative applications in music production. LFOs can be used to create a wide range of effects, including:

  • Creating evolving pads and soundscapes

  • Shaping rhythmic patterns

  • Pulsating basslines

  • Adding stereo panning and movement to tracks

  • Enhancing the depth and spatial perception of your mix

Let’s explore these applications further.

Evolving Pads and Soundscapes

LFOs can be used to create evolving pads and soundscapes, adding an atmospheric dimension to your music. By modulating parameters such as filter cutoff and resonance,

LFOs can transform a simple, static sound into a rich, evolving soundscape.

For instance, using a slow sine wave LFO to modulate the filter cutoff can create a beautiful, sweeping effect, with the sound gradually brightening and darkening over time.

Similarly, using a fast square wave LFO to modulate resonance can create a rhythmic, pulsating effect, adding a sense of movement and rhythm to your pads.

These techniques can be used in a variety of musical genres, from ambient and electronic music to film scores and sound design.

low frequency oscillation for Rhythmic Patterns and Pulsating Basslines

Rhythmic Patterns and Pulsating Basslines

Rhythmic patterns and pulsating basslines are another creative application of LFOs.

By modulating parameters such as volume, pitch, or filter cutoff, you can create engaging rhythms that complement your compositions.

For instance, using a square wave LFO to modulate volume can create a pulsating rhythm, adding a sense of groove and movement to your basslines.

Similarly, using a sawtooth wave LFO to modulate pitch can create a rising and falling effect, adding a sense of tension and release to your rhythms.

These techniques can add a rhythmic backbone to your tracks, driving the energy and momentum of your music.

Stereo Panning and Movement

Stereo panning and movement can add a sense of depth and space to your mix.

By using LFOs to modulate panning, you can create a sense of movement, making your tracks feel more dynamic and immersive.

For instance, using a slow sine wave LFO to modulate the pan position can create a sweeping effect, with the sound moving from left to right in a smooth, fluid motion.

Similarly, using a fast square wave LFO to modulate the pan position can create a more dramatic, back-and-forth effect, adding a sense of tension and excitement to your mix.

Implementing these techniques can elevate your music, infusing it with vibrancy and a sense of vitality.

A photo comparing analog and digital synthesizers

LFOs in Synthesizers: Analog vs Digital

Analog and digital synthesizers, though different in their construction and sound production, both utilize LFOs to modulate parameters and create dynamic sounds.

However, digital synthesizers offer more advanced modulation options and complex routing capabilities, opening up a world of sonic possibilities.

So, let's investigate the use of LFOs in both analog and digital synthesizers.

Analog Synths

Analog synthesizers, with their warm, organic sound, make extensive use of LFOs to modulate parameters. This results in dynamic sounds that have a distinct analog character, rich with depth and complexity

For instance, as seen before, you can use an LFO to modulate the pitch of an oscillator, creating a vibrato effect.

Or you can use it to modulate the filter cutoff, creating a rhythmic, pulsating effect.

The are a lot of possibilities, and the resulting sounds are uniquely analog, with a warmth and richness that’s hard to replicate digitally.

Digital Synths

On the other hand, digital synthesizers offer more advanced LFO options, opening up a world of creative possibilities.

With digital synths, you’re not limited to a single LFO. You can use multiple LFOs to modulate different parameters, creating complex and evolving sounds.

Again, as seen before, you can use one LFO to modulate the pitch of an oscillator, creating a vibrato effect, while using a second LFO to modulate the filter cutoff, creating a rhythmic, pulsating effect.

Or you can use an LFO to modulate the rate of another LFO, creating complex, evolving modulation effects.

The possibilities here are even more vast, and the resulting sounds can be incredibly intricate and rich.

An illustration of LFOs in effects processing such as chorus and flanger

LFOs in Effects Processing

Effects processing is another area where LFOs can work their magic. LFOs can be used to create a variety of effects, including:

  • Swirling chorus

  • Flanger effects

  • Psychedelic phasers

  • Rhythmic tremolos

LFOs, through LFO modulation, play a crucial role in shaping the character of your effects as the LFO oscillates.

We should examine how these effects processing techniques utilize LFOs.

The Flanger Section in Cubase Retrologue

Chorus and Flanger

Chorus and flanger effects use LFOs to modulate the delay time, creating a swirling, spatial sound that can add depth and richness to your mix.

The chorus effect, for example, uses an LFO to modulate the pitch of a duplicated signal, creating a shimmering, thickening effect.

On the other hand, the flanger effect uses an LFO to modulate the delay time of a duplicated signal, creating a sweeping, jet-like sound.

By adjusting the rate and depth of the LFO, you can control the speed and intensity of these effects, adding movement and animation to your sounds.

The Phaser Section in Cubase Retrologue

Phaser and Tremolo

Similarly, phaser and tremolo effects also make use of LFOs.

The phaser effect uses an LFO to modulate the phase of a duplicated signal, creating a sweeping, whooshing sound that’s often associated with psychedelic music.

The tremolo effect, on the other hand, uses an LFO to modulate the volume of the signal, creating a rhythmic pulsing or shaking effect.

By tweaking the rate and depth settings of the LFO, you gain command over the tempo and strength of these effects, injecting your music with a rhythmic flair.

Low Frequency Oscillation Cubase Tool

Mastering LFO Techniques in Steinberg Cubase

Steinberg Cubase is a robust digital audio workstation that offers powerful tools for mastering LFO techniques. With its user-friendly interface and advanced modulation options, Cubase can help you take your LFO skills to the next level.

Let’s examine the ways to modulate parameters and work with multiple LFOs in Cubase.

Modulating Parameters in Steinberg Cubase

Modulating parameters in Steinberg Cubase allows for precise control over LFO effects.

Cubase offers a range of tools for parameter modulation, from the Auto LFO plugin, which is compatible with MIDI CC, to the ability to modulate third-party plugin parameters by making adjustments to specific settings within the plugin.

Whether you’re modulating a synth’s filter cutoff or a delay effect’s feedback level, Cubase gives you precise control over the modulation parameters, allowing you to shape your sounds exactly as you want.

With Cubase, you can create everything from subtle modulation effects to dramatic transformations, all with a few clicks of the mouse.

Working with Multiple LFOs

Working with multiple LFOs in Cubase enables the creation of intricate modulation effects, resulting in unique and engaging music productions.

Cubase allows you to create modulation modules that can be used as a source by any parameter capable of automation, allowing for the creation of intricate modulation effects.

For instance, you can use one LFO to modulate the pitch of a synth, while using a second LFO to modulate the filter cutoff, creating a complex, evolving sound.

Or you can use an LFO to modulate the rate of another LFO, creating a complex, evolving modulation effect. With Cubase, the possibilities are vast, allowing for a level of creativity and complexity that’s hard to match.

LFO Summary


As we’ve seen, Low Frequency Oscillators (LFOs) are essential in shaping the character and movement of sounds in music production.

From defining the rhythm and texture of a sound with varying wave shapes, controlling the speed and intensity of modulation with rate and depth, to creating complex and evolving sounds with routing options, LFOs provide a world of possibilities for creating dynamic and engaging music.

Whether you’re working with analog synths, digital synths, or effects processing, mastering the art of LFOs can significantly enhance your sound design skills. And with powerful tools like Steinberg Cubase, you can take your LFO skills to the next level, modulating parameters and working with multiple LFOs to create unique and engaging music productions. So, go forth, experiment, and let the power of LFOs transform your music.


Frequently Asked Questions

Which Oscillator is Used for Low Frequency?

An LFO (Low Frequency Oscillator) is used for low frequency, typically below 20 Hz, and is out of the range of human hearing. It is utilized to influence parameters in synthesis to create movement and depth in sound.

What is an Example of LFO?

An example of an LFO is when it's used in electronic music, such as in dubstep and drum and bass, to create a "wobble" effect in bass sounds by modulating the cutoff frequency of a low-pass filter. This is a common practice that adds dynamic movement to the music.

How Does LFO Work?

LFOs work by generating a slowly oscillating signal that can be used to modulate other parameters in a synth or effect. For example, it can be routed to modulate the pitch of an oscillator to create a vibrato effect.

What is the Main Function of an LFO?

The main function of an LFO is to operate at frequencies below 20Hz and is primarily used for modulation rather than sound production.

How do Wave Shapes Affect LFO Modulation?

Wave shapes like sine, square, triangle, and sawtooth have distinct effects on sound modulation, producing a variety of modulation effects and textures.

About the Author

Max Porcelli

Steinberg Certified Trainer, DJ, and Producer with 29 years of experience. He owns 989 Records, an Electronic Music Label based in Italy. Every Saturday he hosts an exciting Radio Show called 989 Records Radio Show on air on Patchouli Deep Radio, London. 
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