Multiple two-step oscillation regimes produced by the alto saxophone

Area of Science:

• Acoustics
• Musical Instrument Physics
• Fluid Dynamics

Background:

• Saxophone sound production relies on reed vibration and acoustic coupling.
• Understanding complex reed oscillations is crucial for instrument design and performance.
• Previous studies identified basic oscillating regimes in wind instruments.

Purpose of the Study:

• To experimentally identify and characterize different oscillating regimes of a saxophone reed.
• To compare experimental findings with a simplified acoustic model of the saxophone.
• To investigate the influence of blowing pressure and control parameters on reed behavior.

Main Methods:

• Utilized a saxophone mouthpiece equipped with sensors to measure reed oscillation and internal acoustic pressure.
• Employed the harmonic balance method for theoretical analysis of a simplified saxophone model.
• Used measured input impedance in the acoustic model.

Main Results:

• Identified qualitatively different oscillating regimes, including two closures per cycle and inverted regimes (longer closure than opening).
• The experimental results showed qualitative agreement with the harmonic balance simulation.
• Both experiments and simulations demonstrated that various regimes appear in the same order as blowing pressure increases.

Conclusions:

• The study reveals complex reed dynamics in saxophones, extending beyond the standard two-step regime.
• A simplified acoustic model can reproduce observed phenomena, validating theoretical approaches.
• Blowing pressure is a key parameter controlling the transition between different oscillating regimes.