Google Chromecast Audio: Stream your favorite music with Google Chromecast Audio. Simply plug into your speaker's auxiliary input and connect to your Wi-Fi network. Then just tap the Cast button from your favorite apps on your phone, tablet or computer to cast songs, radio stations and podcasts to your speaker.
I connected Chromecast audio with Bose Cinemate 1 SR home theater using optical fiber for my home background music. Source is Spotify. Excellent sound quality. Cons: no much software support Chromecast yet.