Audio

I have been trying to get audio to play through my Primary computer.  I am using the IP address.  When I attempted to set it up it displays an error about not finding any Playback devices and if I would like to override it.  I say yes, it requires a reboot, try again, same process.  I did find that if I plug in a portable USB speaker it works great.  I hope / doubt that I need an actual speaker connected to use this feature.  Anybody have advice on how to configure my system to make it think it has a audio playback device, but it really doesnt.  Or should I buy a cheap speaker and call it a day?