Volume 117, Issue 1, January 2005
Index of content:
- MUSIC AND MUSICAL INSTRUMENTS 
117(2005); http://dx.doi.org/10.1121/1.1815132View Description Hide Description
Stopped-pipe jet-excited musical instruments are known in many cultures, those best-known today being the panpipes or syrinx of Eastern Europe and of the Peruvian Andes. Although the playing style differs, in each case the instrument consists of a set of graduated bamboo pipes excited by blowing across the open tops. Details of the excitation aerodynamics warrant examination, particularly as the higher notes contain amplitudes of the even harmonics approaching those of the odd harmonics expected from a stopped pipe. Analysis shows that the jet offset is controlled by the fluid dynamics of the jet, and is such that appreciable even-harmonic excitation is generated. The theory is largely confirmed by measurements on a player.
117(2005); http://dx.doi.org/10.1121/1.1803574View Description Hide Description
Besides radiating sound from the note area being struck, a steelpan radiates from neighboring note areas that vibrate sympathetically, from the areas between notes, and from the skirt [Rossing et al., Phys. Today 49(3), 24–29 (1996)]. Measurements were taken in an anechoic chamber using a four-microphone intensity probe to visualize the acoustic radiation from selected notes on a double second and a low tenor steelpan. Swept sinusoidal excitation was effected using an electromagnet. Sound intensity maps were drawn for the first three harmonics.
117(2005); http://dx.doi.org/10.1121/1.1828572View Description Hide Description
The paper discusses the application of numerical optimizing techniques to musical structures. It is shown that the natural tendency to emulate the instrument maker by optimizing the characteristic frequencies of the structure is not always the most appropriate strategy, and that in cases where one or more possible solutions exist it is more appropriate to specify the frequency requirements as a constraint. The strategy is illustrated using a xylophone bar.
Predicting the similarity between expressive performances of music from measurements of tempo and dynamics117(2005); http://dx.doi.org/10.1121/1.1835504View Description Hide Description
Measurements of tempo and dynamics from audio files or MIDI data are frequently used to get insight into a performer’s contribution to music. The measured variations in tempo and dynamics are often represented in different formats by different authors. Few systematic comparisons have been made between these representations. Moreover, it is unknown what data representation comes closest to subjective perception. The reported study tests the perceptual validity of existing data representations by comparing their ability to explain the subjective similarity between pairs of performances. In two experiments, 40 participants rated the similarity between performances of a Chopin prelude and a Mozart sonata. Models based on different representations of the tempo and dynamics of the performances were fitted to these similarity ratings. The results favor other data representations of performances than generally used, and imply that comparisons between performances are made perceptually in a different way than often assumed. For example, the best fit was obtained with models based on absolute tempo and absolute tempo times loudness, while conventional models based on normalized variations, or on correlations between tempo profiles and loudness profiles, did not explain the similarity ratings well.
117(2005); http://dx.doi.org/10.1121/1.1828511View Description Hide Description
The purpose of the work reported here is to further experimentally explore the wide variety of behaviors exhibited by driven vibrating wires, primarily in the nonlinear regime. When the wire is driven near a resonant frequency, it is found that most such behaviors are significantly affected by the splitting of the resonant frequency and by the existence of a “characteristic” axis associated with each split frequency. It is shown that frequency splitting decreases with increasing wire tension and can be altered by twisting. Two methods are described for determining the orientation of characteristic axes. Evidence is provided, with a possible explanation, that each axis has the same orientation everywhere along the wire. Frequency response data exhibiting nonlinear generation of transverse motion perpendicular to the driving direction, hysteresis, lineargeneration of perpendicular motion (sometimes tubular), and generation of motion at harmonics of the driving frequency are exhibited and discussed. Also reported under seemingly unchanging conditions are abrupt large changes in the harmonic content of the motion that sometimes involve large subharmonics and harmonics thereof. Slow transitions from one stable state of vibration to another and quasiperiodic motions are also exhibited. Possible musical significance is discussed.