A pilot study on the use of an electroacoustic approach to characterize acoustic waveguides

• A simplified approach is proposed to determine the specific acoustic impedance of waveguides as those found in ventilation systems, exhaust mufflers, or flow-generating devices. • Electrical impedance measurement data of an electrodynamic speaker used as an acoustic sensor served to derive the specific acoustic impedance of the whole waveguide. • Experimental results agree with those obtained with the transfer function method for different waveguide impedance terminations. The acoustic characterization of waveguides is of great importance in the noise assessment of ventilation systems, exhaust mufflers, or flow-generating devices. This task is typically performed by positioning acoustic sensors along the waveguide, allowing the interior sound field to be analyzed. However, some of these devices may exhibit accessibility issues, which prevent the practical characterization thereof and urge the need for alternative methods. In this study, an electroacoustic approach that relies on the measurement of the electrical input impedance of a speaker coupled to a waveguide is proposed to obtain the specific acoustic impedance of the latter. This approach not only overcomes the above practical limitations but also avoids the need for microphones in the characterization procedure. Preliminary results show good agreement when compared to those obtained using the well-established transfer function method for different waveguide impedance terminations and highlight the potential of the proposed approach for characterization purposes.