Aeroacoustics of Musical Instruments

Abstract

We are interested in the quality of sound produced by musical instruments and their playability. In wind instruments, a hydrodynamic source of sound is coupled to an acoustic resonator. Linear acoustics can predict the pitch of an instrument. This can significantly reduce the trial-and-error process in the design of a new instrument. We consider deviations from the linear acoustic behavior and the fluid mechanics of the sound production. Realtime numerical solution of the nonlinear physical models is used for sound synthesis in so-called virtual instruments. Although reasonable analytical models are available for reeds, lips, and vocal folds, the complex behavior of flue instruments escapes a simple universal description. Furthermore, to predict the playability of real instruments and help phoneticians or surgeons analyze voice quality, we need more complex models.

Evidence of biphonation and source–filter interactions in the bugles of male North American wapiti (Cervus canadensis)

“…ring doves: Riede et al, 2004;songbirds: Riede et al, 2006;gibbons: Koda et al, 2012;sopranos: Sundberg, 1975sopranos: Sundberg, , 1979, the clear modulation of a source by a resonance, as observed here, has not been previously reported for putative biomechanic laryngeal sources (despite being predicted by simulations using a model of vocal fold tissue vibration based on morphological and biomechanical features of the wapiti vocal apparatus, if the impedance of the source and the impedance of the vocal tract were comparable; Titze and Riede, 2010). However, strong coupling is widely expected in aerodynamic sources (Fabre et al, 2012), lending further credence to the hypothesis that G0 represents an aerodynamic, rather than biomechanic, source. Interestingly, the locking/jumping of G0 onto specific resonances is also highly reminiscent of the behaviour of flute-like musical instruments (Fabre and Hirschberg, 2000).…”

“…(1) Vortex-induced whistles can be produced when a flow of air is forced through a narrow constriction (usually coupled with a Helmholtz resonator) such as the lips and the oral cavity in human whistling. (2) Flute-like whistles can be produced when a flow of air forced through a narrow constriction ( jet) impacts a labium (see Fabre et al, 2012). Video footage shows that vapour is exhaled at a reduced rate through the mouth during bugling before a much larger volume of vapour is expelled at the end of the vocalisation.…”

Flow-excited acoustic resonance of a Helmholtz resonator: Discrete vortex model compared to experiments

“…Because of its practical importance and fascinating physics, the studies on the flow-acoustic coupling phenomenon can be dated back to as early as Lord Rayleigh 1 and have received much attention since 1950s. [2][3][4][5][6] The flow-excited resonance in a Helmholtz resonator results from the coupling of the shear layer instabilities over the opening with the acoustic mode inside the cavity via a feedback loop. Generally, cavity resonance can be classified into three categories in terms of the type of acoustic feedback.…”

Direct numerical simulation of fluid–acoustic interactions in a recorder with tone holes

“…In the oscillations in flue instruments, the feedback loop is formed. 1 The vorticity perturbations are induced at the flue exit due to acoustic particle velocity, which are amplified into jet oscillations, and the acoustic radiation occurs by the interaction of the jet oscillations and the edge. This acoustic radiation drives the acoustic resonance in the resonator.…”