Hey there! Sorry to hear that your DIGITS app is giving you some troubles! I just did a few test calls myself and I was unable to reproduce this disconnecting error and the audio quality sounded fine for the caller.
What version of the desktop app are you using currently? Also, have you tried playing with your microphone output settings in your computer's sound manager when the callers are telling you that you sound low?
Happy Saturday, arcticzeroo!
Are you still experiencing dropped calls while using the Desktop for DIGITS? If so, please take a look at Chris' reply above and answer a few questions so we can look into this for you.
I can no longer reproduce the issue either ¯\_(ツ)_/¯
I think disabling all other recording devices seems to have solved it, for some reason it must have been selecting the wrong one to use (it's odd that there is no option).