Constant Buzz sound from Speakers

[grphon97]

I have three devices. A computer, a PS4 Pro, and my Z623 Logitech speakers.

When I connect either the PS4 OR the computer to the speakers, the speakers operate as expected without a constant buzz sound.

When I connect BOTH the PS4 AND the computer to the speakers, a low (frequency AND volume) constant buzz sound begins.

Neither of these situations cause issues with the quality of sound coming from the speakers. It still sounds great. Thus, I attribute this to power consumption but I need to know a few things.

1. Why is this happening if there exists multiple ports to plug in multiple devices?
2. How do I avoid this without having to repeatedly unplug and plug devices causing material degradation of the ports?
3. If I keep both plugged in and let the buzz sound continue, will it cause a problem in the future that I should know (Damage to any device, risk of blowing up my electrical outlet)?

Thanks

 

[americanaudiophile]

You are getting a ground loop.
http/web.mit.edu/~jhawk/tmp/p/EST016_Ground_Loops_handout.pdf
The grounds of the PC and PS4 are connected through the speaker and through the grounds of the AC cords. You can try using a 3-2 ground lifter on the PS4 to see if that gets rid of the hum. Another option would be
https/www.amazon.com/PAC-Ground-Isolator-3-5-Applications/dp/B001EAQTRI/ref=pd_bxgy_e_img_y
It's doubtful the buzz will damage anything but I would find it annoying.