Wirelessly play audio from an iPad to a Mac
The AirServer application may offer the functionality that you're looking for. According to this 2011 review, the app can:


  AirPlay is what lets you throw content from an iPad or iPhone
  wirelessly to speakers or your TV. To do this, you need to have an
  AirPort Express next to your speakers, or an Apple TV hooked up to
  your TV. Bluetooth speakers show up in the list, too. What you can’t
  do is beam movies from your iOS device direct to your big-screen iMac.
  
  AirServer is a $3 app that adds in this last piece of the puzzle. With
  it running on your Mac, a new entry will show up in the AirPlay
  popover of any iOS device on the same network, as you’d expect.
  
  Music just appears magically from your Mac’s speakers, or whatever
  speakers are hooked up to it. Movies open after a second in the
  Quicktime player, and it’s on-screen controls let you play, pause,
  scrub and change volume on the Mac itself.


According to the link on the AirServer website, the price for the current version (AirServer 4.0) is $14.99.

Another application with similar functionality is Banana TV. However, it doesn't support iOS 5, as this note on the app homepage states:


  Banana TV has moved to free. We will not be supporting iOS5, although
  the latest build DOES support Lion. You need an iPhone or iPad running
  greater than or equal to iOS 4.2 and less than iOS 5.0. We apologize,
  but keeping up with Apple's continual change of the undocumented,
  private AirPlay interfaces just isn't something we can continue!


Both applications allow for media to be played from an iOS device to a networked Mac.

EDIT: Add current price of AirServer application.