Relationships between pressure, flow, lip motion, and upstream and downstream impedances for the trombone

Abstract

This experimental study investigates ten subjects playing the trombone in the lower and mid-high range of the instrument, B♭2 to F4. Several techniques are combined to show the pressures and the impedance spectra upstream and downstream of the lips, the acoustic and total flows into the instrument, the component of the acoustic flow due to the sweeping motion of the lips, and high speed video images of the lip motion and aperture. The waveforms confirm that the inertance of the air in the channel between the lips is usually negligible. For lower notes, the flow caused by the sweeping motion of the lips contributes substantially to the total flow into the mouthpiece. The phase relations among the waveforms are qualitatively similar across the range studied, with no discontinuous behavior. The players normally played at frequencies about 1.1% above that of the impedance peak of the bore, but could play below as well as above this frequency and bend from above to below without discontinuity. The observed lip motion is consistent with two-degree-of-freedom models having varying effective lengths. These provide insight into why lips can auto-oscillate with an inertive or compliant load, or without a downstream resonator.

La acústica de los instrumentos musicales de viento - metal

“…Ha habido trabajo importante en esta área, pero todavía hay mucho que no entendemos. [7][8][9] Del mismo modo, casi todos los ejecutantes de estos instrumentos creen firmemente que los efectos de las vibraciones del instrumento tienen un efecto significativo en el sonido. Esto ha demostrado ser cierto en el caso de las vibraciones de la campana 10 y se ha propuesto una teoría para explicar el efecto, 11,12 pero no está claro que las vibraciones de otras partes del instrumento afecten al sonido.…”

Laryngeal flow due to longitudinal sweeping motion of the vocal folds and its contribution to auto-oscillation

“…2. Subject to the conditions listed above, positive work is then performed by the pressure difference (P 1 À P 2 ) over one complete cycle (Boutin et al, 2015) solely due to the swinging motion of the vocal folds. This work done can overcome losses, and might provide a significant contribution towards autooscillation, particularly in cases where the phases of the load impedances may not be favorable.…”

Acoustic dissipation in wooden pipes of different species used in wind instrument making: An experimental study

“…Indeed, the acoustic dissipation inside the bore is linked to the amplitude and the width of air column resonances. Then it affects the relative contribution of the vocal tract impedance and consequently the range of playable notes around the bore resonances, as shown by experimental studies on the saxophone (Chen et al, 2011) and the trombone (Boutin et al, 2015).…”