Simcenter Testing Solutions Simcenter Testlab Array Data Reporting

Microphone arrays are fast and reliable tools to localize sound sources and quantify their contribution. Array data measurements are straight-forward: the array is pointed at the object under test, and microphone data, pictures and video images are all measured in a single shot. Analyzing individual runs requires a little bit of expertise, although the process itself is quickly understood. 

But how to be more efficient and productive, when the goal is to analyze and compare multiple datasets or frequency ranges at the same time? This article gives some common processing and analysis scenarios.

Contents:
1. Loading Array Data Reporting
2. How to get an overview of sound sources?
3. How to display multiple results?
4. How to compare different datasets?
5. How to display and compare sound power results?
6. Interested in more?

1. Loading Array Data Reporting

Array Data Reporting is a powerful tool to analyze microphone array data. It is targeted on efficiently selecting, displaying, and comparing data from Simcenter Testlab HD Acoustic Camera and Simcenter Testlab 3D Acoustic Camera workbooks.

Array Data Reporting consist of two Simcenter Testlab add-ins, Array Data Selection & Comparison, and Array Batch Processing:

• The Array Data Selection & Comparison add-in is a free add-in on Desktop and can be considered the ‘desktop for Sound Source Localization’.
• Array Batch Processing is available without license for those users that have Simcenter Sound Camera Digital Array software, Simcenter Testlab: HD Acoustic Camera, or Simcenter Testlab 3D Acoustic Camera. It is also available with Simcenter Testlab Tokens.

These two add-ins are turned on under "Tools -> Add-ins" in the main Simcenter Testlab menu as shown in Figure 1:
 

• How to get an overview of sound sources?
• How to calculate multiple results?
• How to compare different datasets?
• How to display and compare sound power results?

• Select the 3rd octaves of interest
• Calculate all results in a single step
• Expand the result, so that they appear as separate entries in the results list
• Display will automatically arrange the results in the 4x3 grid

3. How to display multiple results?

The next scenario is how to calculate and display multiple results in one or more datasets. That could be for example to localize sources belonging to different peaks in a spectrum. Or for non-stationary events, different time segments in the same recording.

The video below shows how to create multiple results:


Direct YouTube results: https://youtu.be/pny2RpqTPt70
 

• The spectrum display shows the averaged Array spectrum: that gives an overview of the phenomena captured by all microphones. This can be done for mulitple array databases, making it easy to find the differences
• The time display can be switched from Time to Colormap: a colormap of time-vs-frequency gives a very good overview of all the sound phenomena that are present in the data
• Time segments and frequency ranges can be set for multiple results at the same time
• In the Array Data Viewer, Ctrl-A selects all displays. A single display can be selected with Shift-Click. The same operation is used to deselect. 
• Once multiple holograms are selected, the properties of all displays can be changed in a single operation. The hologram can be zoomed with the mouse wheel or moved; it will be applied to all selected holograms. Also, the scales can be aligned for all selected displays are the same time. 

4. How to compare different datasets?

The next scenario extends the previous one and shows how to compare multiple results over one or more datasets. 

When analyzing multiple datasets, that could be to do a comparison before/after a modification, or to compare different design variants.


Direct YouTube link: https://youtu.be/h1E1L2c3MW8


In video highlights the following features:

• Apply the same processing, but to different results
• Align scales
• Organize results in the 4x3 grid

5. How to display and compare sound power results?

The final scenario shows how to process sound power results, and how to define and compare groups of different components.

When the Enhanced Resolution add-in is loaded, it’s possible to process with any of available advanced methods: iNAH, Bayesian Focusing, CIRA and Clean-SC. What they all have in common is that they produce sound power results. That can be used to quantify the contribution of a specific components, or even the whole object, by means of a microphone array. 

In Array Data Reporting that’s done by first changing the processing result from Pressure to Power (Pressure/Power column) and set the method to any of the available methods (Method column). In the example below it shows Bayesian Focusing. Afterwards it is then possible to define groups and display as sound power spectrum (Type column), which will add an additional 2D graph.


Direct YouTube link: https://youtu.be/V2GyGQJHYiU


Takeaways of the video are:

• Change from Localization to Quantification results
• Select the processing method from the Enhanced Resolution add-in
• Define groups
• Display the power spectrum result

6, Interested in more?

Check out these blogs:
•    What is Bayesian Focusing
•    The Science of Music

Or these links:

• Index of Testing Knowledge Articles
• Simcenter Sound Camera - Everything You Need to Know
• Simcenter Testlab: HD Acoustic Camera
• Simcenter Testlab: Sound Power Calculation with HD Acoustic Camera
• Simcenter Testlab: Improving Low Frequency Results with Acoustic Array
• History of Acoustics
• Sound Pressure
• What is a decibel?
• What is A-weighting?
• Octaves and Human Hearing
• What is Sound Power?
• Decibel Math
• What is the Acoustic Quantity called Q?
• Sound Absorption
• Sound Transmission Loss
• Noise level certification, how to select the right standard?
• Sound pressure, sound power, and sound intensity: What is the difference?
• Sound fields: Free and diffuse field, near and far field
• Loudness and Sones
• Auditory Masking
• Tone-to-Noise Ratio and Prominence Ratio
• Fluctuation Strength and Roughness
• Critical Bands in Human Hearing
• Kurtosis
• Sound Quality Jury Testing

Questions?  Email charles.rice@siemens.com.