Volume 125, Issue 3, March 2009
Index of content:
- TRANSDUCTION 
125(2009); http://dx.doi.org/10.1121/1.3075594View Description Hide Description
On-axis and far-field series expansions are developed for the sound pressure due to an arbitrary, circular symmetric velocity distribution on a flat radiator in an infinite baffle. These expansions are obtained by expanding the velocity distributions in terms of orthogonal polynomials with the Legendre polynomials. The terms give rise to a closed-form expression for the pressure on-axis as well as for the far-field pressure. Furthermore, for a large number of velocity profiles, including those associated with the rigid piston, the simply supported radiator, and the clamped radiators as well as Gaussian radiators, there are closed-form expressions for the required expansion coefficients. In particular, for the rigid, simply supported, and clamped radiators, this results in explicit finite-series expressions for both the on-axis and far-field pressures. In the reverse direction, a method of estimating velocity distributions from (measured) on-axis pressures by matching in terms of expansion coefficients is proposed. Together with the forward far-field computation scheme, this yields a method for far-field loudspeaker assessment from on-axis data (generalized Keele scheme). The forward computation scheme is extended to dome-shaped radiators with arbitrary velocity distributions.
125(2009); http://dx.doi.org/10.1121/1.3075582View Description Hide Description
By means of numerical computation, pulse mode of a piezoelectric radiator in the form of a plate, loaded with a liquid and connected to circuits in various combinations, is investigated. The computations were carried out having taken into account the internal resistance of the electric generator. Numerical results, based on the theory, are provided for examples of parallel and series circuits connected to a piezoelectric plate. The optimal values of parameters are determined, providing minimal duration of radiated acoustic pulses.