Thanks for responding--!
It's not a RF buzzing noise -- I know what that sounds like. It's the "clicks" and operating noise of the Lacie SSD drive when I write files to it. It sounds like one of those old platter hard drives working and it's emanating from the speaker.
I checked, and know for a fact my Lacie external drive is a 500 GB SSD drive -- not a hard drive.
I know it sounds crazy, but the noise is there, and I wouldn't be spending my time here just for kicks. I noticed it when I first hooked the Macbook up a couple months ago. As I mentioned, my older Macbook Pro 2012 was fine with the same drive and all the same hardware (audio interface, speakers, etc.) This leads me to believe that since the new Macbook Pro 2017 is the only hardware component that was changed, and now there is the noise, it looks like it narrows down to the new Macbook Pro being the culprit.
Also, when I purchased the Macbook, I had to also purchase $200 worth of Apple dongles in order to hook up my various thunderbolt 2 devices to the USB-C ports on the new Macbook. Is it possible that the dongles could be to blame?
Interestingly, there was another post in a similar thread here that had the same problem with a new 2017 Macbook Pro. They said they took it to Apple, got a warranty replacement, but the problem persisted with the new laptop. I don't think they reposted an update, but I'll check---
This is why I'm trying to get to the bottom of this-- no one has a solution, although I certainly do appreciate the ones that are trying to help me.
I'm in the process now of dealing with Lacie support, and I'll update here what happens.