Chromecast Audio is new music focused product from Google. For just $35, you can connect any speaker set you own to Chromecast. It supports Google Play Music, Spotify, Rdio, and others. Apple Music isn't supported, so you'll want to look elsewhere if you've chosen to use it. Chromecast includes RCA, 3.5mm, and optical inputs so it'll be compatible with just about any setup you have. It works on Mac, PC, iOS, and Android. It's essentially an audio only "AirPlay type adaptor"

At $35, Chromecast Audio is an inexpensive way to enjoy your music on your existing speakers.