After reading Geoff Lindsey's introduction to the vowel space, I wished that I could hear what it would sound like to move around the vowel space in real time. This page lets you do just that!
In the upper right is a modified version of Neil Thapen's Pink Trombone, a vocal tract simulator generating real time audio based on factors like tongue position, lip position, throat constrictions, pitch, and intensity. Everything is click-able!
In the lower right is the resulting sound wave that you hear (turn on your speakers!).
In the lower left is the sound wave's spectrum, a representation of the different frequences that make it up. The pitch determines the spacing of the spikes, and the vocal tract determines their height. The dashed blue lines shows the predicted heights based on the vocal tract shape.
Notice that there are a few gentle peaks in the heights of the spikes that don't change with pitch. These peaks are formants, and they're what define vowels! The formants are numbered from left to right: F1, F2, F3, and so on.
In the upper left are a two different ways to visualize formants. On the bottom is a plot of the predicted intensity of the spectral peaks based on the shape of the vocal tract. The lines are where my peak finding algorithm thinks it's found a formant.
On the top is the main event: the vowel space. This is a plot of the first formant (F1) against the second formant (F2). As the values of these first two formants change relative to each other, the circle on this plot will move – and – if you move the circle, the simulator will update accordingly! The letters are the IPA symbols for the different standard vowels.