Modulation means changing the property of sound over the course of time. It adds motion, dimension, and depth to sounds. The process requires a source signal that controls another signal. The source signal is the modulator, whereas the controlled signal is a carrier. Modulators don’t create sounds, but they do change them by manipulating the parameters that affect the source signal.


There are several types of modulators; LFOs, ADSR envelopes, mod wheels, and step sequencers are the most common ones.

A Bit About LFOs

Low-frequency modulators (LFOs) are essential within the modulation process because they create repeating signals that control a destination source. Waveform shapes define the behavior of this repeating signal. LFO modulation can change the amplitude and speed of a signal. This focuses on the filter frequency cutoff.

A Bit About ADRS envelopes

ADSR envelopes focus on attack, decay, sustain, and release. They do so in order to shape the timbre of a sound or to modulate other parameters. Several elements can trigger modulation envelopes, such as sidechain input, user input, or by a simple note. Filter frequency cutoff is a typical modulation target.

A Bit About Mod Wheels and Step Sequences

On the one hand, mod wheels is an expression control on a synth. On the other, step sequencers can modulate several parameters on a synth. In addition, they can create simple or complex rhythmic patterns through programmable modules.

Modulation Effects

Modulation effects add depth width, movement, and character to sounds. The most common modulation effects are chorus, flanger, phaser, tremolo, vibrato, auto-pan, and LFO. Firstly, the chorus effect adds richness, stereo width, and thickness to sounds. Secondly, flanger creates complex harmonic sounds. Thirdly, phaser adds harshness to sounds. Fourthly, tremolo rhythmically changes the volume of a signal and creates gentle or intense pulsating effects. In addition, the sixth element on the list, vibrato, modifies the pitch of a signal and creates a sense of movement and rhythm while helping sounds stand out in a mix. Finally, the auto-pan effect changes the panning position and manipulates the amplitude of a signal. 

There are other synthesis techniques that use modulation to produce sounds, including frequency, ring, and amplitude modulations.

Modulation: Conclusion

As a final note, modulation makes music more interesting. However, an excessive amount use can ruin the mix.