Measurements of exhaled air effects in the pitch of wind instruments

The present paper deals with measurements of the sounding frequency of wind instruments as a function of the ever-changing gas contents of the player’s respiratory system. During the playing process with a wind instrument, the carbon dioxide level continuously increases, while the oxygen percentage decreases. These two variables are taken into account for the calculation of the expected pitch variation. An experiment is run to measure the effective variations occurring with the recorded sounds, under constant blowing pressure and with the use of a device that replaces the natural embouchure. The results show a systematic fall in the fundamental frequency that amounts to almost 20 cents for long tones in the oboe