Comparison of methods for processing acoustic intensity from orthogonal multimicrophone probes

Area of Science:

• Acoustics
• Signal Processing

Background:

• Four-microphone orthogonal probes are used for acoustic intensity estimation.
• Various processing methods exist, but their comparative performance is not well-understood.

Purpose of the Study:

• To investigate and compare the errors associated with different processing methods for acoustic intensity estimation using orthogonal probes.
• To evaluate probe configurations, including freely suspended and sphere-embedded microphones.

Main Methods:

• Comparative analysis of signal processing methods for acoustic intensity.
• Simulation of propagating plane-wave fields at various incidence angles.
• Error assessment for different microphone placements (free-field vs. sphere-embedded).

Main Results:

• The lowest error for acoustic intensity magnitude is achieved with sphere-embedded microphones and a single microphone for pressure estimation.
• The lowest error for acoustic intensity direction is obtained with sphere-embedded microphones and Taylor approximations for particle velocity and pressure.

Conclusions:

• Sphere-embedded microphone configurations offer superior accuracy for acoustic intensity estimation.
• The choice of pressure estimation and particle velocity approximation significantly impacts the accuracy of acoustic intensity measurements.