Virial relations between the BH mass M_BH = f × M_vir and the average VP given by the mean FWHM (once the Hβ has been converted into Hα) and the mean L_{2−10 keV} (using Eq. (4) to convert L_{14−195 keV}). In the top panels the black hole masses have been calculated assuming ⟨ f ⟩ = 4.31 (Grier et al. 2013), while in the bottom panels two different f factors, f_CB = 6.3 for classical bulges and f_PB = 3.2 for pseudo-bulges (Ho & Kim 2014), have been adopted to determine M_BH. All the VPs are normalized as specified in Eq. (2) (see Tables 3, 4 for the resulting best-fit parameters). In the left panels the total calibrating sample is shown, while in the middle and right panels the sub-samples of classical (red filled squares) and pseudo-bulges (blue open squares) are shown separately. The lines show the best-fitting virial relations derived for each sample.