Accurate sound sources are essential for calibrating outdoor acoustic sensor networks used in technical and environmental monitoring. This study investigates a ducted loudspeaker with flush-mounted microphones as a sound source with known power output and uniform radiation. The power outflow is determined using a mode decomposition method taken from duct aeroacoustics that enables quasi real-time source strength estimation in indoor and outdoor environments. For low-frequency applications, a single-microphone method is proposed that integrates mode decomposition with prior numerical analysis. The approach is validated in a reverberant field, showing agreement with ISO 3741, ISO 3744, and sound intensity methods. Furthermore, directivity patterns are determined via experiments and a numerical model. Error analysis highlights the importance of an accurate reflection coefficient at the duct termination in achieving an accuracy within 2 dB, which is comparable to established standards. The method is successfully applied to generate an outdoor infrasound source with known power output and uniform hemispherical radiation, making it suitable for calibrating inaccessible sensors, such as CTBTO stations or distributed microphones in smart cities.
CC BY 4.0 ; Creative Commons Attribution 4.0 License
Themenbereich der Metrologie
Akustik, Ultraschall, Beschleunigung
Geschäftsfelder
Grundlagen der Metrologie
Förderinformationen (1)
Förderername: Deutsche Forschungsgemeinschaft (DFG)
Förderer ID: 0000 0001 2096 9829
Förderer ID Typ: ISNI
Titel der Förderung: UAV basierte Nahfeld Fernfeld Transformation
Förderungsnummer: JA 3325/4-1
Zitierung
Subramanyam, R. R., Castro Mota, R., Wittstock, V., & Jacob, S. (2025). Synergizing mode decomposition and numerical analysis for creating sound sources with known power output: Application to an outdoor infrasound source. Measurement, 255, 1–13. https://doi.org/10.1016/j.measurement.2025.117956
