Did something like this for janky whole-venue music at my wedding reception back in '07. We had a low power FM transmitter connected to a laptop playing the music. We borrowed a bunch of old "boom boxes" with FM radios from friends, tuned them to our "station", and arrayed them throughout the event space. We kept the volume fairly low on each radio so we didn't have to worry about echoes.

Shilling for an old employer. This is a neat super simple device that takes incoming headphone and converts to FM.

Whole House FM Transmitter (https://wholehousefmtransmitter.com/)

You don't even need a Raspberry PI.

You can simplify it even further. List of things you need.

1. Smartphone or DAP.

2. Car Bluetooth FM Transmitter (~$20)

3. USB to 12 V car adapter(~$10)

4. Existing FM radio.

You can set this up in 5 minutes. Connect the smartphone/DAP using BT or AUX cable. Select a free FM channel and you are ready to go.

Also, in the photos, the FM antenna is fully extended which is unnecessary as these FM transmitters put out plenty of RF power.

P.S. On AliExpress, you can buy both for < $15 while on Amazon it is around $30.

P.P.S. Just the USB FM transmitter is only $5 on AE. For the cost of a cup of Coffee!

For those looking for technical details, Github, "Pi FM Kitchen Radio Station" <https://github.com/trwmato/pi-fm-kitchen-radio>.

NB: Not my project, but it tickles an interest.

Here in Germany you have to be careful when setting up a homemade radio signal - it might be illegal depending on frequency and transmit power.

I personally prefer a combination of

  duckdns.org
  Beets
  Navidrome
  Audiobookshelf
  Substreamer / DSub 
  PaulWoitaschek/Voice / Audiobookshelf
  Wireguard

You can even make a script do download smart playlists to usb-sticks for kitchen radios without wifi or old car USB.

This is rad.

I miss the experience of having career professionals 100% dedicated to the music world curating a list of what I would hear. Of course, it was not perfect, there were ads, most stations played pop slop, but most of the time there was a few stations for your taste, your knew your preferred DJs times and there was a certain sense of community in being a regular fan of a show.