By this option, a subsequent weighting can be applied to the entered spectrum while the setting for the spectrum weighting on the dialog Spectrum remains unchanged. So, when selecting a specific weighting on the dialog Modify Spectrum causes a recalculation and thus a modification of the spectrum originally entered.
From the list box, the selected weighting can be applied to (A, B, C, D) or removed from the spectrum (-A, -B, -C, -D).
This is option is just relevant to sound power spectra.