The particularity of electronic music is its nonlinearity compared to other music genres. Of course, rock, pop or even jazz can borough effects. However, these music genres are traditionally evoking a given timbre or sound characteristic which doesn’t change over time. Modulation in electronic music is a buzzword. Nonetheless, it is precisely this subtle modification which triggers the listener’s interest in the latter genre.

I. Modulation (music) | Definition & Basics

As explained, modulation signifies a change in the perceived sound. When we talk about electronic music, we will often refer to a property of a sound such as amplitude, pitch or timbre, which can be “modulated” over time.

Nonetheless, modulation doesn’t only apply to electronic music. It exists and is noticeable in many different things in everyday life. You can hear modulation in a voice or modulation in guitar strings. All sounds that are altered over time can be referred to as modulated signals.

If in real life the change of the modulated signal can be chaotic and uncontrolled, the producer will generally use modulation for a calculated purpose. Therefore, most of the time modulation in electronic music will be periodic and repetitious, altering functions such as pitch or cutoff.

For the sake of originality and in genres such as experimental music, modulation can be random. In that case, the producer will (most of the times) record modulation without consciously thinking it will produce the expected result.

II. Modulation | The Tools

After having understood what modulation is, it is essential to look at the tools which are employed to produce that particular effect in electronic music. Before looking at the different “modulation units” you will find in your daw of choice, let’s understand how you modulate a sound signal.

The central tool around modulation is the LFO or low-frequency oscillator. The latter is applied to the sound you want to modulate. Interchangeable with the process itself, essentially, modulation is simply an LFO.

What is an LFO? The LFO corresponds to a waveform at a very low frequency that is usually not audible to the human ear and which is added to the original oscillator or to a function such as a volume to modulate that function.

On most hardware and software synthesizers, you will find modulation, given the central role it plays for sound design. A physical example would be the modulation wheel you can often find on the right of a MIDI keyboard.

As that wheel is increased, more LFO is added into the signal and therefore we have more modulation. In general, modulation is used for the application of vibrato. The latter effect adds an interesting whirly modification through the LFO to the original oscillator and this results in a perceived modulation of the pitch.

The vibrato effect can be replicable and audible in a voice, guitar note or other sources of sound. Therefore, it is the combination of waveform and LFO, that produces modulation and the only way to obtain modulation in electronic music is through the use of an LFO.

The LFO you will find in the completest synthesizers gives the possibility to alter the original sound-wave by the modification of diverse sound characteristics such as pitch, pulse width, mix, cutoff resonance, volume, filter FM, LFO amp.

Notwithstanding, in the next section, we will see how a whole category of modulation effects exist. Over the time, these have become “classics” in the field of electronic music production. They changed the sound to which they’re applied in interesting, useful, and sometimes radical ways.

III. Modulation | Specific Effect Units & Techniques

In this section, we’ll discuss some of the specific effects which can be categorized as modulation, and explain how they work. However, it is first important to consider how important modulation is. Much like in any subfield, there are different ways to use modulation. If the underlying principle remains the same, slight variations offer very different effects.

As an example in Logic Pro X, there is an entire section dedicated to modulation with effects units such as the chorus, flanger, microphaser, phaser, ringshifter, spreader, tremolo. Modulation effects include many variations on these basic concepts, here are examples of modulation in music:

Chorus

This particular effect attempts to emulate the sound of two or more of the same instruments playing the same parts simultaneously. Due to the impossibility to play two instruments at the same time, this results in successive phase cancellations which will thicken the original sound.

Ensemble

combines up to 8 standard chorus modules with two LFOs and a random LFO for deeper, richer chorus effects.

Flangers & phasers

Historically, phasers came first. Like chorus units, phasers are digital effects that work by dividing the incoming signal into two copies and shifting the phase of one before recombining it with the original signal again. This produces an effect that is similar in some respects to flanging, but not as powerful and therefore tends to be a less popular effect.

Tremolo

In this case, LFO is used to modulate the volume level, the volume is going up and down. This effect is often used with guitar amps, gives a wave sound of the guitar coming in and out as that volume is adjusted with that LFO.

On a side note, the flanger, phaser, and micro-phaser all use very short delay times and modulation rates to create shifts in timbre and harmonic structure rather than the pitch shifts found to the Chorus effects.

As mentioned earlier, some modulation effects are classics. Phasing and flanging are also classic effects you’ve heard many times, which sound somewhat like the “whooshing” of wind embedded in the sound.

Nonetheless, it is important to note down that all of these modulation effects are essentially variations of the same principle. Namely, the periodical application of LFO to alter sound wave properties such as pitch or amplitude.

As a music producer, these modulation units are undeniable assets in the creative process, and your understanding of how they function will be another asset in the professionalization of your tracks.

Conclusion

Much like any other effect in electronic music (delay, reverb), modulation plays a role in making a track less dull and more enjoyable to the listener. By widening the stereo signal, thickening a traditionally bleak sound, you will improve the presence and overall quality of the elements in your track. However, much like any other effect, modulation should not water down your mix to create a disharmonious ensemble. It should rather be a process you apply with caution to make it just noticeable and pleasing to the listener.