A problem with that is if your opponent is using an expensive PA, its likely to be insulated against the effects of a stun weapon and hardened to withstand EMP as well. If you're looking to disable them, you might think about using something like a sci-fi net launcher or equivalent (like the predator in AVP)... Maybe a foam gun that shoots a fast-drying hard adhesive foam to prevent movement and functionality?
Hmm... Now that I think about it, that's actually a pretty good idea for my own guys to use. -slaps forehead-