This experimental study investigates ten subjects playing the trombone in the lower and mid-high range of the instrument, B♭2 to F4. Several techniques are combined to show the pressures and the impedance spectra upstream and downstream of the lips, the acoustic and total flows into the instrument, the component of the acoustic flow due to the sweeping motion of the lips, and high speed video images of the lip motion and aperture. The waveforms confirm that the inertance of the air in the channel between the lips is usually negligible. For lower notes, the flow caused by the sweeping motion of the lips contributes substantially to the total flow into the mouthpiece. The phase relations among the waveforms are qualitatively similar across the range studied, with no discontinuous behavior. The players normally played at frequencies about 1.1% above that of the impedance peak of the bore, but could play below as well as above this frequency and bend from above to below without discontinuity. The observed lip motion is consistent with two-degree-of-freedom models having varying effective lengths. These provide insight into why lips can auto-oscillate with an inertive or compliant load, or without a downstream resonator.

Trombonists normally play at a frequency slightly above a bore resonance. However, they can 'lip up and down' to frequencies further above the resonance (more compliant load) and below (inertive load). This was studied by determining the pressures, flows and acoustic impedance upstream and downstream and by analyzing high speed video of the lips. The range of lipping up and down is roughly symmetrical about the peak in bore impedance, rather than about the normal playing frequency. The acoustic flow into the instrument bore has two components; the flow through the lip aperture and the sweeping flow caused by the moving lips. Variations in the phases of each of these two components with respect to the mouthpiece pressure allow playing regimes loaded by bore impedances varying from compliant to inertive. In a simple model, this sweeping motion also allows the pressure difference across the lips to do work on the lips around a cycle. Its magnitude is typically about 20 times smaller than the work input to the instrument but of the same order as the maximum kinetic energy of the lips. In some cases, this sweeping work may therefore contribute most or all of the energy required for auto-oscillation.

The physical parameters of a violin bridge have a significant influence on the tonal colouration of its sound. The resonance peaks of the bridge shape the response of the violin body. Reinicke and Cremer developed a simple bridge model that shows a typical broad frequency peak around 2.5kHz, because it incorporates the coupling to the violin body and the soundpost. By using the same model, Jim Woodhouse revealed the effect of some parameters of the bridge (mass, stiffness and foot spacing) on the instrument frequency response. Here the parameters of the violin resonance peaks are changed in real time, by applying an active control method. Such a technique, very useful in noise reduction, enabled to change separately the position and the shape of each peak of the bridge input admittance. On the bridge, 2 actuators and an accelerometer are placed at strategic positions in order to change the peak frequency and the damping factor values. The system behaviour is controlled by a Digital Signal Processor. Some sound results achieved with a real violin back up the theoretical equations.

In this study, the acoustic dissipation is investigated experimentally in wooden pipes of different species commonly used in woodwind instrument making: maple (Acer Pseudoplatanus), pear wood (Pyrus Communis L.), boxwood (Buxus Sempervirens) and African Blackwood (Dalbergia Melanoxylon). The pipes are parallel to the grain, except one which forms an angle of 60° with the fiber direction. An experimental method, involving input impedance measurements with several lengths of air column, is introduced to estimate the characteristic impedance and the attenuation factor in the pipes. Their comparison reveals significant differences of acoustic dissipation among the species considered. The attenuation factors are ranked in the following order from largest to smallest: maple, boxwood, pear wood, and African Blackwood. This order is the same before and after polishing the bore, which is an essential step in the making process of wind instrument. For maple, changing the pipe direction of 60° considerably increases the attenuation factor, compared to those of the other pipes, parallel to the grain. Further, polishing tends to reduce the acoustic dissipation in the wooden pipes, especially for the most porous species. As a result, the influence of polishing in the making procedure depends on the selected wood species.

The ondes Martenot is a classic electronic musical instrument based on heterodyning processing. This paper proposes a power-balanced simulation of its circuit, in order to synthesize the sound it produces. To this end, the proposed approach consists in formulating the circuit as a Port-Hamiltonian System, for which power-balanced numerical methods are available. Observations on numerical experiments based upon this formulation allow simplifications of the circuit in order to achieve real-time computation in home-studio conditions.