Modified CMB spectrum emerging from the DA and EoR, in units of brightness temperature relative to the CMB (Evoli, priv. comm.): a fiducial model without DM (solid line; this is our benchmark model), an extreme model without DM (dashed line), a fiducial model with DM with M_min = 10^-3M_⊙ (dot-dashed line), where M_min is the mass of the smallest DM subhalo, and a fiducial model with DM with M_min = 10^-6M_⊙ (three dots-dashed line).