I know this is an old topic, but I had the same gripe about audio quality in the built-in recording feature for a while. However, as a Mac user, the new Voice Memos app in MacOS, probably available since the Mojave release, allows you to drag and drop from the recording list directly into a note. Even recording with a cheap mic into Voice Memos on your Mac provides vastly better sound quality so I'm happy with this workaround for now.