Method for measuring linear parameter of loudspeaker

Abstract

The invention provides a method for measuring linear loudspeaker parameters by applying the system identification technology to the prior audio measurement instrument. The method uses a special signal to excite a loudspeaker to be tested and obtains the linear loudspeaker parameters by the system identification technology according to a linear impedance model of the loudspeaker and an acoustic pressure theoretical formula through the measurement of voltage and current at two ends of the loudspeaker and the measurement of acoustic pressure signals of the tested loudspeaker at the same time. The method can measure the linear loudspeaker parameters quickly and accurately without measuring the linear loudspeaker parameters by using additional mass or attachment capacity at twice and the vibration displacement by using laser, and is applicable to production lines.

Description

technical field [0001] The invention relates to a method for measuring linear parameters of a loudspeaker. After obtaining a linear impedance curve of the loudspeaker by giving a special excitation signal to the measured loudspeaker, the linear parameter of the loudspeaker is obtained by using a system identification technique according to the established linear impedance model of the loudspeaker and in combination with a sound pressure theory formula. Background technique [0002] The significance of measuring the linear parameters of the loudspeaker: [0003] Loudspeaker linear parameters play an important role in the design, manufacture, and quality control of loudspeakers. Since the 1970s, A.N.Thiele and R.H.Small in Australia proposed several independent small-signal parameters of direct-radiating loudspeakers. These small-signal parameters are used to characterize the low-frequency performance of loudspeakers and are widely used in speaker system (speaker) production a...

AI Technical Summary

Problems solved by technology

[0005] A) The method of discrete frequency measurement, using discrete frequency points to measure the impedance curve of the speaker, so as to obtain fs, Qts and other parameters, and then use the additional mass or additional volume method to measure the impedance curve again, so as to obtain fs', Qts' etc. All the linear parameters are obtained by calculation. The disadvantages of this method are: 1. When using discrete frequency measurement, the test accuracy is low and the test takes a long time, and the operation is troublesome at the same time; 2. Attachment mass and attachment volume method They are all parameters measured by destroying the real working state of the original speaker to a certain extent, so the measured linear parameters are not very accurate, and this method generally requires secondary measurement

[0006] B) Wolfgang.Klippel's paper "Fast and Accurate Measurement of the Linear Transducer Parameters" published at the 110th [International] Audio Engineering Society Conference (Fast and Accurate Measurement of the Linear Transducer Parameters) proposed the use of laser vibration measuring devices to measure speakers Displacement, so as to calculate the linear parameters of the loudspeaker. Although this method is more accurate, it needs to use an additional expensive laser vibration measuring device, which is not suitable for rapid measurement on the production line.

[0007] C) U.S. Patent 6269318 (Method For determining Transducer linear operation parameters) proposes a method for measuring the linear parameters of loudspeakers using voltage-sound pressure transfer function and current-sound pressure transfer function. This method is to use curve fitting technology to compare the two transfer functions For parameter fitting, the calculation complexity is high, and this method needs to provide a test box with a known volume as the condition for accurate measurement

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