Callout to trans women: have you used a voice coaching app? Did it help? Which one did so for you?
The only app I use for voice training is Echo: https://play.google.com/store/apps/details?id=uk.co.projectneon.echo … Hold down the big button to record, instant playback on release. One would assume there are tons of good apps for this simple functionality but many of the ones I tried miraculously managed to screw it up..
