Measurements of acoustic input impedance of wind instruments using two different approaches are presented. In the first approach, commonly referred to as the two-microphone transfer function method, a tube is connected to the instrument and excited with broad-band noise. Signals recorded at microphone pairs placed along the tube are then analyzed to estimate the instrument input impedance. A ca...

Abstract Our previous study has revealed that acoustic resonances have non-negligible effects on photoacoustic signals for a liquid sample confined in thin tube. In this paper, we present numerical and experimental studies the of tube hardness directivity generated signal. A glass capillary silicone 1 mm diameter were tested using pulsed light 637 nm wavelength. Black ink was as material. capil...

Nonlinear acoustic damping is a key nonlinearity in miniature loudspeakers when the air velocity at high amplitude. Measurement of nonlinear beneficial for predicting and analyzing performance loudspeakers. However, general measuring methods impedance, such as standing-wave tube method or impedance method, are not applicable this scenario because coupled with other system nonlinearities. In stu...

Change in impedance of an encircling coil is obtained in the present paper for the case where the electric conductivity and magnetic permeability of a metal cylindrical tube depend on the radial coordinate. The system of equations for the vector potential is solved by means of the Fourier cosine transform. The solution is expressed in terms of improper integral containing modified Bessel functi...

The viscothermal wave propagation of the air inside the resonators is efficiently described by the so-called low reduced frequency model. Using this model, absorption coefficients can be calculated for different configurations. The theory has been implemented together with an optimisation algorithm, so that the dimensions of the resonators can be optimised to satisfy any desired absorption leve...

The variation of the breakdown voltage of a low frequency electrical pulsed discharge due to an external electrode is reported. The discharge tube consists of a thin glass tube having two internal hollow electrodes. A thin copper foil wrapped around the glass tube forms the external electrode. The internal electrodes of the discharge tube are supplied by a flyback converter. Its operating point...

Meng (1997) used the McConnell crosswell data to show that transmitted arrival traveltimes can be extracted from common receiver gathers (CRG) where the effective source is a tube wave generator. In this report I use the McElroy crosswell data to show that reflection events can be extracted from CRG’s where the effective source is a tube wave generator. This result opens the possibility that mo...