Coincident source loudspeakers avoid the response and directivity irregularities seen with conventional spaced drivers in the crossover region. Earlier work has shown that by placing the high frequency driver at the apex of the low frequency diaphragm the directivity of both drivers may be regularized at the crossover frequency. This paper describes the application of finite element and boundary element methods to explore how some simple sources interact with various boundary conditions. A novel geometry giving much-improved bandwidth and directivity is introduced. Simulated results of an idealized high frequency driver using this geometry are compared to those of an idealized direct radiating dome. The implementation of the new design using this novel structure is discussed and measured results from the complete design are presented.
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