LG Ultrafine 5K monitor causes interference with nearby speakers

Hi everyone. I created an account specifically to reply to this thread to say:

1. @JJJohnson3rd: your suggestion solved my issue perfectly! THANK YOU IN ALL CAPS.
2. For everyone else, here's the exact issue/resolution - if you're reading this from the future, I hope this helps you resolve your problems:

MY PROBLEM AND RESOLUTION, SUMMARIZED:

• I've had a pair of KRK Rokit 8 powered monitors forever. Never had any buzzing issues!
• Then, I bought a new MacBook Pro 15 (w/ Touch Bar). At this point, I still didn't have any buzzing issues with the KRKs
• But THEN I bought the LG Ultrafine 5K display, and WHOA, for some inexplicable reason, the right monitor started buzzing like crazy. Like, super crazy to the point where I had to shut the monitor off unless I wanted to wake the neighbors
• I tried everything: new cables, re-installed the drivers, etc. Nothing worked!
• But then I read this thread, and I tried what was suggested above: I simply attached a three-prong to two-prong adaptor to the power cord, and then plugged it right back into the same power outlet
• VOILA! The buzzing is 100% gone, and all is right with the world

Hope this helps someone else with the same issue! Your friend,

JoshBaskin

Isn’t that dangerous?

https://en.m.wikipedia.org/wiki/Cheater_plug

I was also able to solve the issue, but by plugging in the original power adapter for the Mac (not using power from the monitor). It fixed it immediately, but is obviously not ideal. LG support wanted me to send the monitor back to them (again).

Did the same here in the US. Used a three prong to two prong (no ground) adapter. Solved the problem!

I have exact same issue with KRK Rokit 6. installed M-Audio M-Track Hub USB monitoring interface and it completely eliminated interference. Audio sounds amazing now and i think even bettter than straight from MBP but it's disappointing that there is this issue to begin with.

Literally a very similar issue. Only started happening recently. Have the Rokit 8's, if the monitor is plugged in to the MBP, there's this annoying buzzing. The thing is, there's nothing plugged into the monitor, so not sure where the interference is coming from.

I found lifting the ground pin (am in the uk) through a continental adaptor sorted this for me. Think basically the Thunderbolt ports on the monitor aren't earthed properly.

Using the original power transformer for the laptop did work for me too. And your right, bypassing the ground is somewhat cavalier.