We report a web service for flute players, ‘The Virtual Boehm Flute’, that provides alternative fingerings which may be easier to play, less awkward to finger and/or more in tune for different circumstances. It also provides possible fingerings for multiphonics (chords). It uses an expert system that predicts the playability of notes from features in the input impedance spectra, based on the pl...

The didjeridu, or yidaki, is a simple tube about 1.5 m long, played with the lips, as in a tuba, but mostly producing just a tonal, rhythmic drone sound. The acoustic impedance spectra of performers' vocal tracts were measured while they played and compared with the radiated sound spectra. When the tongue is close to the hard palate, the vocal tract impedance has several maxima in the range 1-3...

Articles you may be interested in Analysis of feedback control of piezoelectric transducersa) Sound absorption of a finite micro-perforated panel backed by a shunted loudspeakera) Thermal boundary layer effects on the acoustical impedance of enclosures and consequences for acoustical sensing devicesa) Modal decomposition method for acoustic impedance testing in square ductsa) Near field acousti...

We give a mathematical analysis of the “time-reversal mirror”, in what concerns phenomena described by the genuine acoustic equation with Dirichlet or impedance boundary conditions. An ideal situation is first considered, followed by the boundary-data, impedance and internal time-reversal methods. We explore the relationship between local decay of energy and accuracy of the method, and explain ...

In recent years, high-resolution additive manufacturing has enabled a diverse range of low-cost methods for ultrasonic wave-front shaping. Acoustic holograms, in particular, allow the generation arbitrary diffraction-limited acoustic fields at megahertz frequencies from single-element transducers. These are phase plates that function as direct analogs to thin optical holograms. this work, it is...

Abreviations: COPD: Chronic Obstructive Pulmonary Disease; PEP: Positive Expiratory Pressure; CF: Cystic Fibrosis; Log G*: Mucus Impedance; MCI: Mucociliary Clearance Index; CCI: Cough Clearance Index; PDPV: Postural Drainage, Percussion, and Vibration; IPV: Intrapulmonary Percussive Ventilation; ACBT: Active Cycle Breathing Technique; HFCWC: High Frequency Chest Wall Compression; ELTGOL: Slow ...

In this paper, we present a numerical scheme for the propagation of acoustic waves in a heterogeneous medium in the context of the finite volume evolution Galerkin (FVEG) method (M. Lukáčová-Medvid’ová et al. J. Comput. Phys., 183:533–562, 2002). As a mathematical model we consider a wave equation system with space dependent wave-speed and impedance, which is used to study the wave propagation ...