ARRANGEMENT AND METHOD FOR MEASURING THE DIRECT SOUND RADIATED BY ACOUSTICAL SOURCES

摘要

The invention provides an arrangement and a method for measuring the direct sound wrad radiated by an acoustical source under test (e.g. loudspeakers) under the influence of acoustic ambient noise sources Q1 and reflections at acoustical boundaries (e.g. room walls). An acquisition device measures a state variable pt(rm) of the sound field at a plurality of measurement points rm in a scanning range Gm by a sensor and generates a scanned data set PGm,tQ0Q1. Based on this data set an analyzer determines the coefficients CradQ0 associated with expansion functions which are solutions of the wave equation. An identifier uses the scanned data set pGm,tQ0,Q1 for generating parameter information P for the analyzer which are the basis for separating the direct sound wrad from room reflections Wref and other waves wsec scattered at the surface of the source under test. An extrapolator predicts the state variable pradQ0 of the direct sound wrad at any point outside the scanning range Gm by using the coefficients CradQ0 of the wave expansion.

主权项

1. An arrangement for determining direct sound radiated by a sound source under test comprising:
an acquisition device generating a scanned data set by measuring a state variable of a sound field surrounding the sound source under test at a plurality of measurement points wherein the measurement points are arranged in a scanning range and the scanned data set describes the superposition of the direct sound with at least one of the following sound components:
an incoming sound generated by an ambient noise source or by the direct sound reflected on an external boundary,a secondary sound generated by an interaction of said incoming sound with the surface of the sound source under test; an identifier, based on the scanned data set generating parameter information which describes the transfer function between the incoming sound and the secondary sound; an analyzer, based on the scanned data set and said parameter information generating direct wave coefficients associated with an expansion of the direct sound; and an extrapolator, based on direct wave coefficients generating a predicted state variable describing the radiated direct sound field at a defined observation point outside the inner boundary of the scanning range.