Looks like we can't reproduce the issue or there's a problem in the test case provided.
Bug with audio component.
I try launch sencha touch 18.104.22.168 app, packaged in phonegap 2.1 on android 4.1 emulator. Audio player doesn't display.
Did you give it a URL to make sure that the environment handles the audio correct or if the environment doesn't display it when no url to an audio component? Without packaging in phonegap it's displaying for me in the browser.