Alexander Mayer

More experimental evidence favouring the hypothesis of significant wall vibration influence on radiated horn sound

The question whether wall vibrations of wind instruments do or can affect the radiated sound has not been finally answered yet. Instrument makers and musicians make a strong claim that wall thickness, material and conditioning are crucial factors for sound quality and response of wind instruments, while acousticians rather tend to question that claim. Recent experiments on horns are presented favoring the hypothesis that wall vibrations do matter. Although horn sound in general appears to change quite significantly when wall vibrations, particularly those of the bell, are dampened during artificial playing, it becomes more and more evident that more than one single mechanism has to be considered to explain the whole phenomenon. Radiation of the bell as multi‐pole will add directivity and strengthen higher harmonics while absorption by the wall will rather weaken them. Dynamic interaction between air column and oscillating bore profile theoretically depends on broken symmetry. Feedback of structural resona...

Humidity influences on natural Timpani heads

Varying air moisture is an issue timpanists using natural skins have to deal with. Moisture, which in concert halls is often created by the audience or by the musicians on the stage, causes natural skin to loose its tension and therefore flattens the pitch of the instrument. The present paper deals with the effects of moisture on the pitch of timpani with natural skin presenting an experiment for measuring the relationship between air moisture and skin tension resp. pitch variation. An experimental setup has been created where the natural skin head was mounted on a copper shell containing an ultrasonic humidifier. The humidification process was computer controlled in order to establish exact humidity levels. The resulting change of the kettledrum skin parameters was measured using an impulse hammer and force transducers at all mounting points of the tensioning hoop. Stretching parameters have been captured by a special video-system. Measurements have been made in a relative humidity range of up to 91%. Th...

Monitoring saxophone reed vibrations using a piezoelectric sensor

In sound production on single-reed woodwind instruments the reed is oscillating in a frequency related to the length of the resonator. Strain gauge sensors attached to single reeds have been used to capture the vibrations of the reed to investigate articulation techniques on saxophone and clarinet. Reeds can be made from natural cane and also from synthetic materials like oriented polymers or layers of fiber-reinforced polymers. Such synthetic reeds allow to integrate sensors inside the reed during manufacture. However, integrated strain gauge sensors produced signals with high noise, which have been shown not to be ideal for amplification purposes. Replacing the integrated strain gauge with a piezo film sensor greatly enhanced the sound quality of the sensor reeds. With this procedure, electronically augmented woodwind instruments may be constructed for performance, acoustic measurements, and music pedagogy feedback systems.

Influence of strain-gauge sensors on the vibrational behavior of single reeds

Experimental measurements are often used in conjunction with physical modeling to characterize sound generation in musical instruments. Focusing on single-reed woodwind instruments, such analyses have provided accurate descriptions of the coupling between the sound excitation mechanism and the resonator during steady-state regimes. For note transients however, more detailed measurements of the reed vibrations under real playing conditions are required. Therefore, strain gauge sensors haven been placed on a series of clarinet and saxophone reeds, in order to capture the vibrations without interfering with the player. Different ways of attaching the sensors to the reeds are considered and the resulting influence is quantified by means of Laser Doppler Vibrometry and Electronic Speckle Pattern Interferometry.

The influence of braces on the playability of trumpets

The influence of braces on the playability, response and sound properties of the trumpet is an intense discussed subject for players and instrument makers. In addition to the problem of finding the proper position of the braces, inserted braces can produce stress between the instruments tubes. In this paper the influence of the tube stress is investigated. To ensure an adjustable and reproducible stress between the trumpet tubes special adjustable braces in conjunction with a force monitor are used. The results of blind playing tests are compared with spectral analysis of the played sounds. In addition, the acoustic input impedance, the wall vibrations and the transfer function of the instrument are investigated.