This article covers how to do audio replay in Simcenter Testlab Neo (Figure 1). The menus reflect Simcenter Testlab Neo 2021 and higher.
Figure 1: Simcenter Testlab Neo Audio Replay
The Audio Replay feature of Simcenter Testlab Neo allows playback from time histories and their corresponding colormaps. Filters can be applied while listening to isolate sounds. Different sounds can also be played back to back instantaneously through switching.
Contents: 1. Getting Started 2. Basic Audio Replay 3. Replay Icons and Switching 4. Advanced Audio Replay 4.1 Live Spectrum 4.2 Colormap Axes Swap 4.3 Live Filtering 4.4 PWM Filter, Variable RPM Filter, and FRF Filter 5. Segments
1. Getting Started
To use audio replay in Simcenter Testlab Neo, go to “File -> Add-ins” as shown in Figure 2:
Figure 2: Audio replay add-ins available under “File -> Add-ins”
There are two add-ins that enable audio playback:
Basic Audio Replay: Enables equalized and calibrated playback with a highlighted replay trace and playback cursor.
Advanced Audio Replay: Includes the basic replay functionality in addition to interactive filtering. Advanced Audio Replay requires 12 tokens.
The features of each add-in are described in more detail in the next sections.
2. Basic Audio Replay
With the Basic Audio Replay add-in activated, three new items appear in the menus as shown in Figure 3:
Figure 3: With the Basic Audio Replay add-in, an Audio Replay ribbon (1) appears at the top, audio replay properties (2) on the right side, and a play button (3) in the lower left
The three items are:
Audio Replay Ribbon: Allows replay device to be selected
Audio Replay Properties: Key replay settings that are also available in the ribbon
Audio Replay Button: Play button
Playback is initiated by using the play button in the lower left. See the video more details on how basic audio replay works:
To replay sound data, use the following order of operations:
Press the play button in the lower left
Click the speaker icon (Figure 4) in the displays to play a trace
Move the cursor to the desired segment for replay
3. Replay Icons and Switching
During replay, icons appear on data that can be played back. Icons can be used to switch back and forth during replay.
The meaning of the icons is shown in Figure 4:
Figure 4: Icons and their meaning in Simcenter Testlab Neo Audio Playback
NOTE: The relative volume levels of recordings are respected during playback during switching.
It is possible to select the data to replay from frequency domain data in the displays as shown in Figure 5.
Figure 5: It is also possible to replay frequency-domain data (like spectrums and waterfalls) if the throughput is linked in the project
The replay icon appears on the colormap and just needs to be clicked, same as with time domain data.
4. Advanced Audio Replay
For more audio replay options, turn on Advanced Audio Replay (this will also automatically load Basic Audio Replay) under “File -> Add-ins”.
Advanced audio replay enables users to visualize live frequency spectrums of the audio and apply filters real time during playback.
Two areas are added to the menus:
Figure 6: The Advanced Replay icon adds live spectral icons to the ribbon (1) and filters (2)
The two features activated the Advanced Audio Replay add-in are:
Live Spectrum Buttons: In the ribbon, icons appear for creating live spectral data during replay
Filters: The filter area allows users to define filters to be used during replay
4.1 Live Spectrums
Clicking on the “Spectrum live” icon in the ribbon automatically creates a live frequency spectrum display that is active during replay (Figure 7).
Figure 7: The “Spectrum live” button creates a frequency spectrum that is live during replay
Before a spectrum is shown, the PLAY button in the lower left must be pressed.
Click on the “Spectral Map” icon to get a live 3D dimensional colormap as shown in Figure 8.
Figure 8: The ribbon icon “Spectrum map” creates a colormap display that is active during replay
Cursors will move in the map during replay. The frequency resolution of the map is set from the pulldown in the ribbon.
4.2 Colormap Swap Axes
Want to swap the time and frequency axes of the colormaps as shown in Figure 9?
Figure 9: Same colormap, but with time and frequency axes swapped
To swap the axes, right click on the colormap and choose “Options”. In the resulting menu, select “Miscellaneous” and choose ZX or XZ as needed (Figure 10).
Figure 10: Swap axes of colormap under the “Miscellaneous” Tab of the colormap options
The frequency and time axes will be swapped in the display.
4.3 Live Filters
It is also possible to apply filters to the sound during replay as shown in Figure 11.
Figure 11: Add a filter type by clicking on a button (1) and adjust the filter frequency settings with the magenta cursors (2) that appear in the display
In Area 1 of Figure 11, filters can be created and removed. They can also be turned on and off as shown in Figure 12.
Figure 12: Add filters, turn filters on and off, and remove filters
Note that all filters can be switched on and off simultaneously with the “Bypass Filters” icon in the Audio Replay ribbon.
While playing back the data, the filter frequency range can be adjusted by moving the magenta cursors in the display (Area 2 of Figure 11).
Filter types include:
None: No filter is applied.
Low pass: Frequencies below a specified cutoff frequency are passed.
High pass: Frequencies above a specified cutoff frequency are passed.
Notch: A narrow range of frequency is attenuated. The frequency and width are specified.
Band stop: A range (band) of frequencies are attenuated. An upper and lower frequency are specified. For a bandwidth smaller than 10Hz, it is recommended to use a notch filter instead.
Band pass: A range (band) of frequencies is passed. An upper and lower frequency are specified.
Order stop: An order is filtered out. All other content remains. The order and width are specified. A frequency offset can be specified to allow the filtering of PWM induced switching frequencies.
Order pass: Only the specified order remains. All other content is attenuated. The order and width are specified.
FRF Filter: A FRF (engineering units of ratio) can be selected and applied as a filter. This allows different gains and attenuation per frequency.
4.4 PWM Filter, Variable RPM Filter, and FRF Filter
Figure 13: Frequency Offset on Order Filter in Simcenter Testlab Neo Audio Replay
Variable Profile: Another enhancement to order filters is a variable profile. Gain and attenuation values can be entered in dB versus RPM as shown in Figure 14.
Figure 14: Variable profile gain for order filter.
FRF Filter: A What is a Frequency Response Function (FRF)? can be used as a filter. This allows the gain to vary arbitrarily versus frequency. The FRF must be in unitless (quantity: Ratio) in order to work. After adding the FRF filter to the list of active filters, right click on the FRF and choose "Use as Audio Filter" as shown in Figure 15.
Figure 15: FRF Filter in Simcenter Testlab Neo Audio Replay.
For more information about filters and orders, see the following Knowledge articles: