Getting a hum

[Frolicious]

I work at a bar/music venue. The computer is plugged into a mixer that plays to the back of house (powered speakers). Those speakers are plugged into sockets in the ceiling (power). We just hooked up a thunderbolt to hdmi to a hdmi splitter(4way). The hdmi cable going to the splitter is 35ft. The splitter And 4 tv's And 4 cable boxes are plugged into the same sockets in the overhead. And a hum is coming from the powered speakers when the hdmi cable is plugged in to the splitter. I assume we have a ground issue and need an electrician... But I'm hoping there might be an easier fix?

 

[americanaudiophile]

There is a ground loop issue.
There is no ground isolator for HDMI so you will have to attack the problem from the audio or AC end. You can use isolators at the inputs to the speakers. You could also try lifting the AC ground pin of the PC or the speakers.