I have no sound on playback. I’m using windows 7 and Audacity version 2.1.0. exe.installer
if you are using a USB audio device for recording, see here: http://manual.audacityteam.org/man/faq_playback.html#usb
I didn’t use a usb to record, I recorded from a music file. I could hear it while recording.
So you really want self-recording. Play something and Audacity records it.