# A-weighted sound pressure level spectrum (plot_ASPL_fft)

Post-processing documentation
Matlab commandplot_ASPL_fft
Module AC.pp
Description PLOT_ASPL_FFT plots the A-weighted acoustic sound pressure level spectrum
Parameters
Restrictions

### Description

This post-processing allows to visualize the Sound Pressure Level (SPL) with A-weighting. The Sound Pressure Level is depedent of the distance from the source d and of the directivity factor Q . For further informations, please refer to What is the difference between Sound Pressure Level (SPL) and Sound Power Level (SWL) ?.

For this example, the Sound Pressure Level is taken at one meter from the source. The A-weighting has been applied to take into account the human’s ear sensitivity (What is A-weighting?).

### Result

The following figure shows an example of A-weighted SPL on an induction machine at high slip:

A-weighted sound pressure level spectrum
plot_ASPL_fft

One can see that due to numerical effects the spectrum is not discrete. To reduce spectral leakage one can increase the number of revolution as shown in ALG_005 validation case or active the frequency solver of MANATEE.