Volume 121, Issue 1, January 2007
Index of content:
- MUSIC AND MUSICAL INSTRUMENTS 
121(2007); http://dx.doi.org/10.1121/1.2390668View Description Hide Description
This article proposes a characterization of the double reed in quasistatic regimes. The nonlinear relation between the pressure drop, , in the double reed and the volume flow crossing it, , is measured for slow variations of these variables. The volume flow is determined from the pressure drop in a diaphragm replacing the instrument’s bore. Measurements are compared to other experimental results on reed instrument exciters and to physical models, revealing that clarinet,oboe, and bassoon quasistatic behavior relies on similar working principles. Differences in the experimental results are interpreted in terms of pressure recovery due to the conical diffuser role of the downstream part of double-reed mouthpieces (the staple).
Vocal tract resonances and the sound of the Australian didjeridu (yidaki). III. Determinants of playing quality121(2007); http://dx.doi.org/10.1121/1.2384849View Description Hide Description
Traditional didjeridus have a broad range of bore geometries with many details not immediately apparent to a player, and are therefore suitable for examining the relationship between perceived quality and physical properties. Seven experienced players assessed the overall playing quality of 38 didjeridus that spanned a wide range of quality, pitch, and geometry, as well as 11 plastic cylindrical pipes. The ranking of these instruments was correlated with detailed measurements of their acoustic input impedance spectra. Most significantly, the ranked quality of a didjeridu was found to be negatively correlated with the magnitude of its acoustic input impedance, particularly in the frequency range from . This is in accord with the fact that maxima in the impedance of the player’s vocal tract can inhibit acoustic flow, and consequently sound production, once the magnitude of these impedance maxima becomes comparable with or greater than those of the instrument. This produces the varying spectral peaks or formants in the sound envelope that characterize this instrument. Thus an instrument with low impedance and relatively weak impedance maxima in this frequency range would allow players greater control of the formants in the output sound and thus lead to a higher perceived playing quality.
121(2007); http://dx.doi.org/10.1121/1.2384842View Description Hide Description
String instruments are usually composed of a set of strings, a soundboard, and a soundbox with sound holes, which is generally designed to increase the sound level by using the acoustic resonances of the cavity. In the case of the harp, the soundbox and especially the sound holes are primarily designed to allow access to the strings for their mounting. An experimental modal analysis, associated to measurements of the acoustic velocity in the holes, shows the importance of two particular modes labeled A0 and T1 as it was done for the guitar and the violin. Their mode shapes involve coupled motions of the soundboard’s bending and of the oscillations of the air pistons located in the sound holes. The A0 mode is found above the frequency of the lowest acoustically significant structural mode T1. Thus, the instrument does not really take advantage of the soundboxresonance to increase its radiated sound in low frequencies. However, contribution of mode A0 is clearly visible in the response of the instrument, confirming the importance of the coupling between the soundboard and the cavity.