Abstract:
Nonlinear standing waves have been studied in a structure consisting of two lengths of tubing with different diameters. Preliminary theory of this structure is proposed. A 100-W loudspeaker driver is used as a sound source to excite the larger tube of 45-mm diameter through a 10-mm side hole near one end which is closed. The properties of the output at the end of the smaller tube as well as their relation with the input were investigated, and a resonance diagram of the two-tube structure is completed. At the end of smaller tube of 13-mm diameter, a sound-pressure level (SPL) of 176.2 dB has been obtained with a low distortion. Increasing the diameter of the larger tube, it is possible to drive the structure directly with a modern high power loudspeaker to produce high sound intensity in a more extended space. Experiments are in progress. [Work supported by the National Natural Science Foundation of China.]