Combined spectra of soft and SSSs in late- and early-type galaxies. Black and green symbols show the integrated spectrum of all soft sources located outside the stable nuclear burning region for WDs (i.e., located to the right of the thick red line in Fig. 5) in late- and early-type galaxies. Yellow symbols show integrated spectrum of sources matching confirmed SNRs in M 83. Blue and red symbols show the integrated spectra of SSSs, i.e., sources located to the left of and above the stable nuclear burning boundary in late- and early-type galaxies, respectively. The spectra are normalized to the same flux at 0.35 keV. See Sect. 6.1 for more details.