Vibrating Lips
The artificial mouth is capable of playing any brass instrument a human can, but for our experiments a simple straight extendable tube is used. This allows us to shine a laser through the lips and into a photo-diode behind them. Using this setup we can observe the amplitude of the opening of the lips in real time. Microphones are placed inside the "mouth cavity" and the mouthpiece cup to provide information on the pressure functions.
The upper image on the right shows the latest version of the artificial mouth - designed by Orlando Richards with advice from Vince Devine in the JCMB workshop. This version has a few advantages over the previous version, including:
- more representative placement of the lips;
- greater access to the lips;
- lip guides to accurately set the embouchure;
- easily variable and measureable water pressure in the lips;
- accurately adjustable mouthpiece position.
These enhancements are designed to allow greater repeatability of experiments, and increased control over the physical parameters involved.
The middle image shows a transparent brass instrument mouthpiece which allows the motion of either a real brass players lips or the artificial lips to be recorded using, for example, a high speed digital video camera. The resulting lip motion can be seen in the bottom animation of Professor Murray Campbell's lips recorded using this system.
