amplitude – Synthesizer Online

Modulation

In a synthesizer, modulation refers to using one signal to control or change another signal. To do this, a signal called the modulator can be routed to control a signal called the carrier’s parameter. An LFO or an envelope generator, which generates a control signal that can be used to modulate different sound parameters, serves as the modulator in most cases.

In synthesizers, the following modulation types are most frequently used:

Amplitude modulation: This involves using an LFO or envelope generator to modulate a sound’s amplitude (i.e., the loudness). This can create effects like tremolo (a modulation of the amplitude at a low frequency) or envelope-controlled volume changes.
Frequency modulation (FM): This involves using one oscillator (the modulator) to modulate the frequency of another oscillator (the carrier). This creates complex, harmonically rich timbres and can create a wide range of sounds, from bell-like tones to metallic and percussive sounds.
Phase modulation (PM): This is similar to FM, but instead of modulating the frequency of the carrier, it modulates its phase. The result is a more subtle, detuned effect that can create chorus, flanger, and phaser effects.
Pulse width modulation (PWM): This involves modulating the width of the pulse waveform of an oscillator. This creates a variation in the harmonic content of the sound and can be used to create a wide range of timbres.
Filter modulation: This involves modulating the cutoff frequency of a filter to create effects like filter sweep and envelope-controlled filtering.

These are only a few applications for modulation in the shaping and sculpting of synthesizer sounds. Modulation is a primary factor that makes synthesizers such potent and versatile instruments, and the possibilities are essentially endless.

ADSR Envelopes

An envelope in a synthesizer is a control signal that modifies a sound’s amplitude and other properties over time. Attack, Decay, Sustain, and Release are its four main parameters (often abbreviated as ADSR).

Attack: controls the time it takes for the sound to reach its maximum amplitude after a note is played.
Decay: controls the time it takes for the sound to decrease from its maximum amplitude to the sustain level.
Sustain: controls the level of the sound while the note is held.
Release: controls the time it takes for the sound to decrease from the sustain level to silence after the note is released.

Subtractive synthesis relies heavily on envelopes, frequently used in sample-based, FM, and physical modeling synthesis techniques.

An envelope in a synthesizer is a control signal that gradually alters a sound’s amplitude and other properties. Attack, Decay, Sustain, and Release are its four primary parameters. By shaping the amplitude and other parameters like the filter cutoff frequency, pitch, and others, these parameters can control how the sound changes over time. To produce dynamic and expressive sounds, they can also be modulated by other synthesizer elements, such as LFOs and velocity. They are an essential component of subtractive synthesis and are frequently applied to other synthesis techniques.