 -0.0cm ![Spectrum of dipole (in equivalent thermodynamic, or CMB, temperature) expressed as the difference between that produced by a distorted spectrum and that corresponding to the blackbody at the current temperature $T_0$. Thick solid lines (or thin three dots-dashes) correspond to positive (or negative) values. [*Left*]{}: the case of BE distortions for $\mu_0=     -0.0\times00^{-0}$ (representative of adiabatic cooling; green dots, note the opposite signs with respect to the cases with positive $\mu_0$), $\mu_0= 0.0\times00^{-0}$, $0.0\times00^{-0}$ (representative of improvements with respect to FIRAS upper limits), $\mu_0= 0.00\times00^{-0}$, $0.0\times00^{-0}$, and $0.0\times00^{-0}$ (representative of primordial adiabatic perturbation dissipation). [*Right*]{}: the case of Comptonization distortions for $u=0\times00^{-0}$ (upper curves) and $u=00^{-0}$ (lower curves), representative of imprints by astrophysical or minimal reionization models, respectively. []{data-label="fig:Dip_C_BE"}](DipAmp