Turn your android device to a wireless set?
I would like to know what do you mean by 'share audio'? Is it sharing music Files or streaming music. If it is about sharing Music Files, you may use Xender from PlayStore which can send files over WiFi to any other user having Xender installed. For PC, you may use AirDroid from PlayStore to access any file or separately any Music File from any Browser on PC over Wifi. 

If Streaming is your goal, I suggest running a HTTP or FTP server on your android device. You can select the app that suits you from here.