This java applet simulates sound waves in the human vocal tract to make vowel sounds. The vocal tract acts as an acoustic filter to shape the spectrum of the sound produced by the vocal chords. To produce different vowels, we move the tongue and lips to create a filter of a certain shape; these shapes produce the desired vowel sounds. If we make a tube with similar length and cross section, and excite it with a source similar to the vocal chords, we can make sounds that sound like vowels. The applet simulates this process by calculating the frequency response of such a tube and creating a digital filter with the same response.

When starting up, click the "Sound On" checkbox to turn the sound on. The applet will be playing an "ah" sound. You can change the vowel sound using the "Filter" popup menu at upper right. You can also make a whisper-like sound by changing the "Input" popup menu to "Noise".

Full screen version.

Original Java version.