jsdafx – Digital Audio Effects in JavaScript

Delay-Based Audio Effects

This script demonstrates audio effects resulting from delay-based algorithms. It is designed for a first insight into the perceptual experience of one amplitude-modulation and three delay-based audio effects: tremolo, vibrato, chorus, and flanger.

Tremolo is the rapid repetition of one note in music terminology or a rapid alternation between two or more notes (string instruments, mandolin, flute, piano, harpsichord, spinet, guitar). In technical terminology tremolo is a rapid repetitive increase and decrease in volume. The effect is based on modifying the time domain envelope (amplitude) of a signal.

Vibrato is the rapid and repetitive variation in pitch for the duration of a note (string instruments, guitar, singing voice, yodeling). In technical terminology the effect is based on modifying the pitch of a signal by delay line modulation (phase modulation).

Chorus simulates the result of an ensemble of musicians (singers, violins) playing together with slight pitch and amplitude differences. The chorus effect performs a loudness increase. These amplitude and pitch differences are simulated by amplitude modulation and delay line modulation (phase modulation) and all signals are summed together to form the output signal.

A flanger simulates a special filter effect wich occurs if a slowly time-varying single reflection is added to the direct signal (jet airplane effect). This effect was achieved by playing two copies of a single signal from two tape machines while slowing down the replay speed of one tape machine by placing a finger to the flange of one tape reel.

You can choose between two predefined audio signals or your own local audio file to be processed.

Predefined music signals "Guitar riff 1" and "Guitar riff 2" are licensed under CC0-1.0.