Abstract

This thesis deals with the construction of a four-microphone impedance tube as an extension of an existing two-microphone impedance tube. Besides the acoustic parameters reflection factor, absorption coefficient, acoustic impedance and admittance, which are determined with the transfer function method using the two-microphone impedance tube, also the transmission factor and the transmission loss of acoustic absorbers can be determined using the transfer matrix method.

The theory of the transfer-function-method and the transfer matrix method is described and the resulting parameters are defined and explained.

When adapting the theory, there is a focus on the calibration of the measuring system.

Then, the hardware of the four-microphone impedance tube is presented, and the software development with the program and data structures are described in detail.

A description of the measuring system, which is written as a user manual and a few selected sample measurements for the evaluation of the measurement system is the completion of the work.

Full Text and additional Material

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