Djs-sx3 loud static noise randomly throughout my weddings

I do about 2 to 3 weddings every weekend. The route one wedding randomly really loudly through both speakers I will get a loud static noise sometimes with a little screech mostly loud static. This scares the gas. This can be 1 to 4 times in an event. I’ve change the outlets. I’ve changed cables. I have brand new cables now. Are use Cerrado DJ pro and it is up to date. I have a MacBook Pro with High Sierra on it. I have an I 7 , 16 GB RAM.

Why am I getting this loud static noise. Is this something Carmen that’s been going on? This was before I got it serviced for the recall. And it has been after I’ve got it serviced for the recall. Can anybody help me?