Audiout is described as 'Menu-bar mixer for Mac audio. Out of the box, only Apple's Music and TV apps can play to every room. Audiout does it for whatever your Mac is playing: Spotify, a browser, a game. It sends audio to AirPlay 2, AirPlay 1, Bluetooth, and Chromecast speakers at once' and is a Audio Router in the audio & music category. There are four alternatives to Audiout for a variety of platforms, including Mac, iPhone, iPad, Windows and Linux apps. The best Audiout alternative is FineTune, which is both free and Open Source. Other great apps like Audiout are SonoBus, Airfoil and AirPlay.