Banshee generated a psionic field which protected him from the detrimental effects of his sonic vibrations, though his sonic powers could still injure him when pushed beyond safe limits. For a while, his sonic powers were gone after having to use them up and down the harmonic scale to stop a weapon of Moses Magnum's. His physiology seemed fully vulnerable to conventional injury when his sonic powers were not engaged. Banshee had selective hearing, enabling him to focus upon, enhance, or totally block out any given sound in his environment; this shielded him from the deafening sound of his own screams, and made him a superhumanly acute eavesdropper in surveillance situations. Sean and his cousin Black Tom were immune to each other's natural mutant energy powers, though Sean's immunity did not extend to the new powers Tom later developed via artificial mutations.