Displaying Levels in a Spectrum Window

The Partial levels tool allows you to calculate the levels in one or more user-defined frequency bands. The frequency bands are delimited with cursors.

To Display the Overall Level and the Weighted Partial Levels:

  1. Select View > Partial levels to display the Levels dialog box.
  2. In Weighting, select None, A, B, or C weighting to apply the selected weighting to the partial levels.
  3. For each spectrum in the window, the Overall levels values indicate the equivalent level, according to the frequency weighting selected above.

    The overall level indicated here is calculated as the (dB) sum of the current spectrum values for each frequency bin. It is therefore highly dependent on the spectrum display which is currently set (Display Options for the Spectrum Window). For example,

    • if the current spectrum display is Third Octave, the overall level will indicate the sum of the individual levels of all the third octave bands, which can be different to the overall level Leq of the original signal.
    • if the current spectrum display is RMS, the overall level will indicate the sum of the individual levels of the RMS spectrum, which can be different to the overall level Leq of the original signal.
  4. In Cursors, click the drop-down button to set the starting point and ending point to proceed to and automatically display Delta F level calculation.

The Overall level and the weighted partial levels are displayed.