Patent ID: 6223853
Filing Date: 2001-05-01
Classification: H04R

Abstract:
A method of tuning an acoustic filter of a loudspeaker system to produce a desired response, said method comprising:providing at least one acoustic waveguide having an inlet and an outlet, for conducting sound waves from said inlet to said outlet;partitioning said at least one acoustic waveguide into two or more sections, each section being of sufficient length to be definable accurately by a distinct characteristic impedance and length whereby it behaves predominantly as distributed elements, said partitioning including forming at least one impedance discontinuity along the length of the at least one acoustic waveguide;modelling the loudspeaker system including said acoustic filter such that the acoustic waveguide sections are represented in the model as distributed elements, said modelling including simulating said system including said acoustic filter by means of an equivalent electrical circuit in which acoustical and mechanical elements in said system including said acoustic filter are represented in said circuit as equivalent electrical components;optimizing said model to produce said desired response, said optimising including adopting initial values for said equivalent electrical components, analysing said circuit to produce a simulated response and comparing the simulated response to the desired response, and if said simulated response is not substantially equal to the desired response, modifying the values of said equivalent electrical components and/or the number of waveguide sections and repeating said optimizing step with the modified values of said equivalent electrical components replacing the initial values; andif said simulated response is substantially equal to said desired response, converting the modified values of said equivalent electrical circuit into acoustical and mechanical elements and incorporating the acoustical and mechanical elements in said system.