Low Pass Filter is used for keeping the lower frequencies on the output signal while eliminating or decreasing the amplitude of signals with frequencies higher. Low Pass Filter can be useful in noise reduction purpose provided that the effective signals is lower than the specified frequency and if the audio higher than the specified frequency is noise.
To apply Low Pass Filter in Dexster:
Open your audio file for editing
Select the part of the audio that you would like to apply for the Low Pass Filter
Click on Filters menu and select Low Pass
Adjust the frequency and steepness parameters or select one of the available presets.
Click on Preview button to hear the filter before apply.