LMS Test.Lab Sound Diagnosis
LMS Test.Lab Sound Diagnosis is used to replay sound recordings, apply real-time filters, and calculate sound metrics.
To get started with LMS Test.Lab Sound Diagnosis, go to “Tools -> Add-ins” in the main LMS Test.Lab menu. Turn on “Sound Diagnosis” and press OK.
LMS Test.Lab Sound Diagnosis can be run with 62 tokens. After turning the add-in on, a new worksheet is added to the workflow along the bottom of the LMS Test.Lab software as shown in Figure 2.
Before clicking on the ‘Sound Diagnosis’ worksheet, select some time data for listening from the Navigator worksheet. Browse to a LDSF/throughput file, right click on it, and select ‘Add to Input Basket’ (Figure 3).
Move from the ‘Navigator’ worksheet to the ‘Time Data Selection’ worksheet. Change the Data Source to ‘Input Basket’ and press the ‘Replace’ button as shown in Figure 4.
Time histories should now be showing in the DataSet area (upper left) of the ‘Time Data Selection’ worksheet.
After adding the time histories in the ‘Time Data Selection’ worksheet, now click on ‘Sound Diagnosis’ as shown in Figure 5.
Press the “Make Playlist’ button in the upper left corner as shown in Figure 6.
Time history recordings are now in the Playlist. Choose the ‘View’ checkbox to visualize time histories in the Strip Chart display as shown in Figure 7
Listen by clicking on the ‘Play’ button (arrow icon) as seen in Figure 8. A cursor will track with the sound replay on any time histories displayed in the Strip Chart.
Instantly switch between time histories by clicking on box next to the desired recording. The box turns blue to indicate which recording is being replayed. After clicking on the blue box, the up and down arrow keys can also be used to switch which sound is being played.
It is convenient to instantly switch between sound recordings for comparison, especially for recordings that were acquired at different times, even months or years apart.
To view a live frequency spectrum while playing sounds, open a FrontBack display in the lower right of the screen as shown in Figure 9.
After opening the display, drag and drop from the display tree. Find the folder ‘Online Data -> Sound Diagnosis (Filtered) -> Instantaneous Spectrum’ and drag the icon labelled ‘Left’ into the newly opened FrontBack display.
If no folders are in the ‘Online Data’ folder, press the ‘Update Results’ next to Display.
When doing sound replay, the spectrum of the sound now updates in real-time in the FrontBack display.
It is also possible to apply filters to the sound in real-time while listening to the replay. This can be useful for identifying sound frequencies that affect the perception of sound.
To add filters, click on the buttons in the ‘Filters’ area on the middle left of the screen. There are several different types of filters that can be added as shown in Figure 10. There is no limit to the number of filters can be added.
Types that can be added include (from left to right) in the filter menu:
For the tracking/order notch filters, if the time history contains multiple rpm traces, scroll to the right in the Filters area to specify the rpm trace to be used for the order filter.
To visualize the filter being used, drag and drop the ‘FRF filter’ icon from the ‘Online Data -> Sound Diagnosis FRF’ folder into the back of the FrontBack display.
While listening, filters can be turned on and off by clicking on the “on/off” toggle icon next to a filter as shown in Figure 12. Cursors can be used to set the frequency values of the filters by toggling on the ‘Edit’ field. Only one filter can have the ‘Edit’ toggle on at a time.
The filter frequency cursors can be changed by moving them in the FrontBack display, even while replay is in progress.
In the FrontBack display, right click on the legend and select “Options…” as shown in Figure 13.
In the ‘Curve Legend Options’ menu, select the middle tab called ‘Calculated Content’ as shown in Figure 14.
All available sound metrics are listed on the left side of the ’Curve Legend Options’ menu. Move the desired metrics from the ‘Available’ area to the ‘Selected’ area by pressing the arrow.
In the ‘Curve Legend Options’ turn on unit label checkbox to see units like “sones” displayed with the single number values. The prefix field can be filled in so a label appears in the legend as well.
Metric values are shown for both the filtered and unfiltered sound spectrum as shown in Figure 16.
Metric values are shown for both the filtered and unfiltered sound spectrum. To overlay the unfiltered data with the filtered data, open the folder ‘Online Data -> Sound Diagnosis (Unfiltered) -> Instantaneous Spectrum’ and drag the icon labelled ‘Left’ into the FrontBack display.
Saving the Work
Use the button “Save Sound Diagnosis” in the lower left to save the Playlist, display settings, filter defintion, etc to a specific run folder within the LMS Test.Lab project. Using the “Load Sound Diagnosis” in the upper left to restore all settings and data.
Enjoy using Sound Diagnosis for listening and metric work!
More Acoustic related links:
More LMS Test.Lab Processing related links: