Apple TV audio through projector

I have an Apple TV connected to a projector and a computer connected to the same projector and control it with a video A B switch. I can mirror my iPad to the Apple TV but I have no audio. I am not sure what I have to do to get audio to my overhead speakers to work while mirroring from the iPad. Audio works if running it with the iPad only but stops when you try to mirror it.

How is the Apple TV connected to the projector?

If you play content direct from the AppleTV rather than via airplay do you get sound?

The Apple TV and a computer are connected to the projector through a VGA splitter and an AB switch. Video works great but audio is a problem.

There are 2 ways audio comes out the ATV.
1. HDMI - feeds both Audio and Video
2. Optical - Feeds only Audio.

You would need a converter to go from the optical signal to a stereo signal via either RCA or Phono plug. OR you need a converter to go from HDMI to A/V.

Beat me to it

And if you are using an HDMI to VGA converter, then you will need to transfer the audio in conjunction with a VGA output with whatever audio output the converter provides.

If the converter only converts the image and not the audio, then you'll need to connect the optical audio out from the ATV directly to the projector.
In conjunction with VGA input, that is likely going to mean using an optical to analog converter like this one.