How to Create Perform A-Weighting Filter Calculation in LabVIEW

Updated Jun 8, 2026

Environment

Software

  • LabVIEW
  • LabVIEW Sound and Vibration Toolkit

You can apply A-weighting to a signal in LabVIEW to approximate how the human ear perceives sound. A-weighting emphasizes mid-frequency components while attenuating very low and very high frequencies, making it suitable for acoustic measurements and noise analysis.
To implement A-weighting in LabVIEW, you will use the Sound and Vibration Toolkit, which provides built-in VIs for applying standard weighting filters.

Follow these steps to apply A-weighting to your signal:

  1. Ensure that the Sound and Vibration Toolkit is installed.
  2. Open your LabVIEW project and create or locate a VI where your signal is acquired or processed.
  3. On the block diagram, place the SVT A, B, C Weighting Filter (Fixed Rates).vi:
    • Navigate to Functions Palette >> Sound and Vibration >> Measurements >> Sound Level.
  4. Wire your input signal to the input signal terminal of the VI.
  5. Select A-weighting from the weighting type input.
  6. Verify that your sampling rate matches one of the supported fixed rates of the VI.
  7. Run the VI and observe the filtered output signal.

After completing these steps, the output signal will reflect the A-weighted response of your original measurement. This means:

  • Low-frequency and high-frequency components are attenuated.
  • Mid-frequency components (approximately 1 kHz–5 kHz) are preserved or emphasized.
  • The signal better represents perceived loudness for human hearing.

Below there is the example of an application performing A-Weighting filtering on simulated sinusoidal signal with the noise. You can see that RMS values are significantly decreased after the filtering. 

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