对音叉接触纸张的“低音”现象研究

Study on the Bass Phenomen on of the Tuning Fork Contacting the Paper

当振动的音叉与纸张存在较弱接触时可以产生低于音叉基频的声音,即为低音现象.在本研究中对这种低音现象进行了理论分析,采用工程学上的"悬臂梁"模型进行分析,再通过考虑其在简谐激励力下的受迫振动,提出了相应的理论模型,明确了影响低音现象的多种关键因素.对于整个系统的振动过程,在实验中以理论中所推导的因素分别从纸张的长度、厚度、宽度、褶皱程度以及音叉与纸张的接触位置这几个方面进行探究,从实验上对理论模型进行定性的验证.

When the vibrating tuning fork is in weak contact with the paper, it can produce a sound lower than the base frequency of the tuning fork, which is the bass phenomenon. In this study, the theoretical analysis of the bass phenomenon is carried out using the "cantilever beam" model in engineering.The model is analyzed, and then the corresponding theoretical model is proposed by considering the forced vibration under the simple harmonic excitation force. The key factors affecting the bass phenomenon are clarified. For the vibration process of the whole system, the theory is used in the experiment. The factors deduced in this paper are explored from the aspects of paper length, thickness, width, wrinkle degree and the contact position of tuning fork and paper. The theoretical model is qualitatively verified experimentally.