Delay-Based Audio Effects

This applet 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 files from our web-server ("audio1.wav" or "audio2.wav") or your own local .wav-file to be processed.

To run the applet you will need at least a Java VM 1.4 or later. Please find the latest JRE (Java Runtime Environment) here.