Motion of brass players’ lips during very loud playing Free

When a crescendo is played on a trumpet, horn, or trombone, the timbre changes markedly at the fortissimo level: there is a dramatic increase in the relative amplitudes of the high‐ frequency harmonics, and the resulting sound is often described as ‘‘brassy.’’ Shock‐wave generation in the air column of the instrument as a consequence of nonlinear steepening of the wavefront is the generally accepted explanation of this phenomenon. It has, however, also been suggested that saturation of the lip opening could play a role in the timbre change. This study compares the motion of the lips at lower dynamic levels and during extremely loud playing, using a high‐speed digital camera and instruments with different sizes of mouthpiece. Curves illustrating the variation of the open lip area as a function of time at different dynamic levels are presented, together with waveforms and spectral analyses of both the radiated sound and the pressure in the mouthpiece. The results suggest that there is no qualitative change in the time‐dependent behaviour of the opening area of the lips when the instrument enters the brassy regime.