Modulation and instability in the sound of plastic soprano recorders
Péter Rucz, Judit M. Angster, András Miklós · The Journal of the Acoustical Society of America · 2017
Soprano recorders are among the most popular wind instruments in music education for children. As these instruments are played by amateurs, they should be easy to play even by beginner players. The investigations reported in this paper were initiated by an instrument maker company. It was found that their plastic soprano recorders often had unsatisfactory sound quality and exhibited hard playability and strange, unstable steady state sounds, especially in the low regime. The experiments reported here were performed in order to examine the characteristic properties of these unusual sounds and to identify the background causes of the observed phenomena. In this contribution the results of various measurements carried out on different plastic soprano recorders are presented. Recorder sounds and edge tones are analyzed in the steady and attack transient states and their key properties are compared. The observed instabilities, strong amplitude modulations and the appearance of subharmonic components in the steady state sound are discussed. Finally, possible physical explanations of the experimental results are examined.