Recording and reproducing speech airflow outside the mouth
Researchers present a system that produces artificial airflow with a similar intensity envelope to that produced during speech, as measured 1 cm away from the lips. They have made an airflow estimator system that does not interfere with speech production. The system consists of a ping pong ball mounted on a carbon fiber lever that flexes a thin, flat, carbon-fiber member to which two strain gauges are affixed on opposite sides. These strain gages are part of a sinusoidal-driven bridge, the output of which, after amplification, is an amplitude-modulated sine wave that is can be recorded using a standard XLR based pre-amplifier into a computer.