TESS and SONG background-corrected, normalised power spectra. The power-to-background ratio (PBR) power spectra from TESS (left column) and SONG (middle) are shown in grey, and a smoothed (box-kernel) version is shown in black. The bottom row shows the weighted average power spectra, where we have taken the power spectrum for each sector or each campaign, divided by the fitted background, and created a weighted average. In the top row we have simply removed (divided) the background from the power spectra resulting from combining all sectors or all campaigns into the time series. The right column shows the product power spectra created from the full time series (top) and the weighted average power spectra (bottom). The insets in the top-left and top-middle panels show the spectral window from the full time series from TESS and SONG, respectively.