The Acoustic Origin of Smiles

You can tell when someone is smiling by the change in tone in their voice. When we smile our cheeks are pulled back, reducing the size of the mouth cavity, thereby raising the pitch of vocal track resonances. Once I get a little free time I think it might be a good idea to analyze this shift in spectrum and design a "smiling" filter setting for audio mastering, to make music smile. The Acoustic Origin of the Smile, by John Ohala.