Ellipsoidal Sound Power Measurement Surface

Estimates the sound power level and sound energy level in an approximate free-field using an ellipsoidal measurement surface.


Updated 23 Aug 2022

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Estimates the sound power level and sound energy level in an approximate free-field using an ellipsoidal measurement surface.
Need information includes: the x, y, and z coordinates of the microphone positions.
The sound pressure level and frequency information.
1) The Device Under Test (dut),
2) Background Noise (bg)
3) Reference Sound Source (rss) data with both the sound pressure level and frequency content.
The reference ellipsoid can be determined from the position and dimensions of the device under test (noise source).
Subprograms use MATLAB programs from the file exchange which are cited in the comments.

Cite As

Edward Zechmann (2023). Ellipsoidal Sound Power Measurement Surface (https://www.mathworks.com/matlabcentral/fileexchange/89559-ellipsoidal-sound-power-measurement-surface), MATLAB Central File Exchange. Retrieved .

MATLAB Release Compatibility
Created with R2019b
Compatible with any release
Platform Compatibility
Windows macOS Linux

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Version Published Release Notes

Updated the arc length estimate on the ellipsoidal surface. Changed the microphone directivity correction, microphone position correction, and normal vector misalignment correction into volume integrals which integrate over the reference volume.


Fixed bugs in the microphone directivity. Microphone Directivity is zero dB for frequencies below the low frequency cutoff.


Fixed bugs in the source velocity term for the oscillating sphere with one or more reflecting planes. Fixed a bug in the sd_round program when SI Prefixes are used. Updated filenames for the piezofootball toss simulations.


Fixed bugs with coercion to using design_3pt_ellipsoid and renamed figure numbers.


Fixed numerous bugs associated with sound power estimates with 2 and 3 abutting reflecting planes, directivity plots, K2 plots, and labels for microphone position plots.


Changed the thumbnail image.


Five programs were added which plot the reference and measurement surfaces. Example output plots are included: reference_surface_plot_1.m, reference_surface_plot_2.m, plot_normal_vector_misalignment.m, ..., plot_normal_vector_misalignment2.m.


This update fixes a bug in the ms_interference_oscillating_sphere.m program. This bug affected the oscillating sphere simulations that had one, two, or three reflecting planes.

This update fixes a bug in the log_scale_nudge.m program.


This update improves the calculations for the influence of microphone directivity on the simulations. Plotting programs were added for the correction due to reflecting surfaces (K2), the sound power (LW), and microphone directivity.


Removed four misnamed files.


Added additional programs for plotting the radiation behavior including:
radiation_behavior_plot1, .... Added additional example testing programs including: test_ellipsoid_weights1, ....


Updated the test files to make sure the variables names were correct.


The method now assumes a centered and aligned ellipsoid. Previous version did not handle offset and rotated ellipsoids with sufficient accuracy. The microphone directivity correction level is now a point estimate at the microphone position.


Added two additional programs with fewer inputs but fewer corrections

LW_LJ_estimate_dut_1.m estimates the sound power level given the dut data.

LW_LJ_estimate_dut_bg_1.m estimates the sound power level given the dut and bg data.


Two description files AA_Contents_H-Lines_2021_03_29.m and AA_Readme.m were not present in the first version.