Using the Periodic Calculator to Produce LMax Values in Frequency Bands

The periodic calculator is a feature of the NoiseTools software that allows you to use the recorded data, such as the time history information, and to recalculate alternative parameters.

Please note that this calculation requires that the 1:3 octave band time history data has been stored at a rate of 1/16 second. If the data is stored at a rate of 1 second, the calculations will not be valid if the measurement is over a short period of time.

The periodic calculator can also be used to process data from a group of measurements. For example, if you’ve made a set of repeating 5-minute measurements and these are collated into a measurement group, the data from all of the measurements can be used as the source information for the periodic calculator.

If you are using a single measurement, the periodic calculator is available from the menu in the top right corner of the summary screen as shown below:

In this example, we will use the 1:3 octave band time history data from a group of measurements to produce an Lmax value for each of the 1:3 octave bands.

Open the measurement group and from the menu on the right side, click Periodic Calculation.

To use all of the available dates, choose “Use Single Period” and click Next. This will concatenate all of the separate measurements into one single period.

Select the Default option to remove any markers from the data and click Next.

The next window allows us to choose the data source and what data we want calculating. In this example, we want to get an LAFmax value for each of the 1:3 octave bands across the whole measurement period.

Note that it is only possible to obtain Fast or Slow time-weighted values with 1:1 or 1:3 octave bands if the data rate as 1/16 second. If the data rate is any slower than this, 1 second for example, the calculation of Fast or Slow time weighting cannot be made.

Select the 1:3 Octave option and choose the first band that we want the data for. 

Next, we need to choose the data type that we want to be calculated for each band. Select the Maximum option, select the Fast Time Weighting and ensure that the Frequency Weighting is set as none.

Click the Add button to select this data type.

To add the next frequency band click the Max (6.3Hz3) in the right column and then select the 8Hz3 in the left-hand column and then click the Add button. This will add the 8Hz band. Repeat this for all of the required bands.

Once you have added all of the required frequency bands into the right-hand column, click Next and the calculator will run and display the results as shown below.

Right-click on the table to export the results into a CSV that can be opened in Excel.

Right-click on the graph to export it as an image.