Hi bvalley
My name is Andre Da Costa; an Independent Consultant, Windows Insider MVP and Windows & Devices for IT MVP. I'm here to help you with your problem.
There isn't a native solution, but I recommend you check out Cloud Convert which I have used in the past convert video files to audio.
https://cloudconvert.com/mts-to-mp3
Note: This is a non-Microsoft website. The page appears to be providing accurate, safe information. Watch out for ads on the site that may advertise products frequently classified as a PUP (Potentially Unwanted Products). Thoroughly research any product advertised on the site before you decide to download and install it.