Hello all. This Windows Movie Maker watery-distorted noise issue seems common but Google search and fiddling on my own have done me no good. 

(Yes, I'm aware WMM is no longer supported by Microsoft but I figured I'd give this a shot anyway.)

I film railroad videos for a YouTube channel with a normal Sony Handycam camcorder, but often I'll additionally use my iPhonee 6s or Nikon D3200 for some back up shots. I use Movie Maker for video editing. 

Here's the big audio issue: My HD camcorder videos (.MTS file extension) are easily editable and work nicely in WMM. Audio is fine and nice quality, even after saving.

However, my files off the Nikon and iPhone are a different story. I am aware WMM is not friendly with .MOV files, which these two devices use.

I've tried converting these .MOV files to both .mp4 and .m4v in several different programs, changed audio quality back and forth, and I still get this same awful watery, distorted static sound after importing and saving with Movie Maker. 

Any help is appreciated. WMM is still my top program for my editing and I'd love to get this solved.