Most ways to stream music to multiple sets of speakers cost more than it is worth. I don't think I have to say much about it, you probably wanted to do this in the past but it just seemed stupid to spend that much money on a separate dedicated system.

We are going to exploit the fact that the Raspberry Pi supports AirPlay (through shairport), and combine it with the 'hack' that allows the Raspberry Pi to transmit FM signals, turning your raspberry pi into a dedicated AirPlay server and FM transmitter.

Here is the best part, the requirements:

1x Raspberry Pi (any model except Pi 2)

1x Long wire (preferably around 2 feet in length)

1x FM radio (many speaker systems and nice alarm clocks have a built in FM radio).