The effect of mounting conditions on the vibration and directivity patterns of the glockenspiel

The glockenspiel is a bright, resonant percussion instrument with a series of simple bars mounted next to each other in a frame. Its acoustic radiation remains underexplored, particularly in its full instrument configuration. This study investigates the acoustic radiation and vibrational behavior of a glockenspiel bar in different mounting conditions. Directivity measurements and the scanning laser Doppler vibrometer were used to compare a single bar in free-free, baffled, and full-instrument configurations. The results show that the mounting significantly alters radiation patterns of the bar, particularly at higher modes. Torsional modes exhibited greater deviation from free-free predictions than bending modes, especially in the full-instrument case. The findings highlight the importance of considering frame and structural interactions in modeling glockenspiel vibration and radiation.