Mass response using the area-based background subtraction method in the 10\% most central \PbPb{} collisions for background fluctuations only (black histogram), compared to the full response including detector effects (red histogram), for anti-\kt{} jets with resolution parameter $R=0.4$. $M_{\rom{sub}}$ refers to the background-subtracted reconstructed jet mass while $M_{\rom{probe}}$ is the jet mass of the embedded probe. From top left to bottom right, each panel represent a $\ptjetch$ region, 40--60, 60--80, 80--100, 100--120$ \GeVc$