Interactive Demonstrations

Below you will find some experiments in speech and hearing that you can try out yourself. Each is recommended by the staff at the Institute; some are educational, some just look and sound nice, but all are fun! You will need a sound card and speakers!


Visualisation of Sound

p-Soup: Interactive Community in Sound. This is a simple but beautiful demonstration of how visual patterns and sound patterns can work together. You might need to wait a couple of minutes for the application to start, and there are no instructions or explanations, but just click anywhere to experience it. If you wait, you may hear interactions by other users! Notice that the horizontal dimension of the display is the pitch of the sound. (This is an updated version of the old Ripple Machine applet).

The Sonification Machine. This is machine that can turn visual patterns into sound. You can draw on the grid and hear different sounds being produced. There are also a number of provided patterns, and some classical experiments in the perception of sound. Be sure to read the description of how the machine works. If you find it interesting, look at this demonstration that uses the sonification machine to convert patterns into speech-like sounds.


The Physics of Waves. Interactive tutorial and demonstrations on the physics of waves.

Decibel Demonstration. An effective audio demonstration of the decibel scale.

Signals and Systems

ESYSTEM: Windows Tool for Learning Signals and Systems Theory. ESYSTEM is a Windows program for experimenting with signals and systems. With ESYSTEM you can see the effect of simple systems on a range of simple signals. You can generate simple signals such as sinewaves, pulses, pulse trains, sawtooth and noise; you can pass them though systems such as an amplifier, a resonator, a low-pass, high-pass or band-pass filter, or a vocal tract model. You can observe the effect on the input and output waveforms and the input and output spectra. You can even replay the input and output sounds. [Windows] NEW: try ESystem web application.

ESYNTH: Windows Tool for Learning Harmonic Synthesis. ESynth is a free program designed to explain the harmonic analysis and synthesis of signals. With ESynth you can create signals by adding together individual sinusoidal waveforms (sinewaves) and study the resulting waveform and spectrum. You can also perform an analysis of an input waveform, to see how a given sound can be represented in terms of a sum of sinewaves. [Windows] NEW: try ESynth web application.

Signal Processing Demonstration Applets. These Java applets from Mississippi State University can be used to learn about: Convolution, Dynamic Time Warping, Filter Design, Pattern Recognition, Pole/Zero Analysis, and Spectrum Analysis.


An Auditory Illusion - tones that always rise in pitch. This is a demonstration of Shepard's auditory illusion: you hear a complex tone that seems to be rising in pitch ... and then you realise that it keeps on rising in pitch!

Auditory Perception Demos from the Internet Psychology Lab. Lots of interactivity in these pages from the University of Illinois, including pitch perception and an audio-visual illusion. Also an interactive introduction to the nature of sound.

Fundamentals of Hearing. Web demonstrations to go with the book "Fundamentals of Hearing" by William Yost. Currently only a nice harmonic synthesis demonstration.

Auditory Animations. Quick-time movies of animations of the operation of the cochlea, plus some sound files simulating hearing impairment. These animations don't have any explanation to go with them, but they look nice.

Hearing Loss Simulator. A Windows program that provides audio simulations of heraing loss. Simulates loss in sensitivity, loss in high frequency and loss in spectral detail. Comes with instructions for demonstration.

Speech Production

X-Ray Videos of Talkers. An impressive collection of x-ray cross-sections of people talking as downloadable movies.

Helium Speech. A remarkable historical tape of Lyndon B. Johnson, the US president talking to a diver breathing Helium/Oxygen mix. Since helium has a lower density than air, the vocal tract resonances of the diver are raised in frequency.

Sulphur Hexafluoride Speech. Breathing a gas heavier than air lowers the vocal tract resonances in frequency. Here are some examples of Helium and Sulphur Hexafluoride speech from the Linguistics department at the University of California Berkeley: here is the same person breathing Air, Helium, and Sulphur Hexafluoride.

Design your own vowels!. A tool to build synthetic vowel sounds from a specification of fundamental and formant frequencies.


PhonWeb - Spoken Phonetic Transcription. A web tool for converting phonetic transcription into synthesized speech. Use it to help learn phonemic transcription of English, or to check your transcription homework!

British and American Vowel Charts. Clickable charts showing the differences between these two accents of English.

Interactive Vocal Tract Saggital Section. Design vocal tract cross-sections to order with this interactive tool.

Speech Technology

History of Speech Synthesis. Audio recordings of historically interesting speech synthesis systems, as originally collected by Dennis Klatt in his 1987 review of English text-to-speech conversion systems.

Demonstrations of text-to-speech conversion programs. These web sites demonstrate software for converting typed text to synthetic speech:


Do you know of other interactive demonstrations? Send us a message.

Copyright © 2017 Mark Huckvale

Last modified: 12:44 19-Oct-2014.