Further investigation of the boundary conditions and directivity of glockenspiel bars

The glockenspiel, a percussion instrument with pitched metal bars mounted in a keyboard-like arrangement, produces sound through mallet strikes. In the standard mounted configuration, the bars are supported by four parallel rails. Two rails hold the top row of bars, while the other two support the bottom row. One end of each bar is secured with a screw, while the other usually rests freely on the rail. The bars’ mounting conditions and vibrational modes significantly influence their acoustic radiation and directivity. While free-free beam theory provides a foundational understanding of individual bar behavior, it does not fully capture the dynamics when bars are played within their mounted configuration. This work continues to investigate the directivity of glockenspiel bars in their standard setup using a directivity measurement system and a scanning laser Doppler vibrometer. This study explores how the bars’ mounting conditions affect their acoustic output by analyzing the vibrational modes and radiated sounds. Comparisons between theoretical models and experimental data reveal how the structure and mounting affect sound radiation. These findings advance our understanding of the glockenspiel’s unique acoustic characteristics, offering new insights into the interaction between vibrational modes and real-world playing conditions.