Vizio's line of SmartCast soundbars and speakers tout Google Cast for wireless audio streaming from a variety of apps. One of those apps is Spotify, a massively popular music streaming service. Unfortunately, the Cast functionality with that particular library of tunes isn't working like it should. There are a number of posts in both Spotify and Google's forums from users who say Vizio's latest soundbars don't show up as an option for Casting in the streaming app. Spotify's software isn't recognizing the speakers as available gadgets for playing music. Reports of the issue go back as far as late July, over a month after the SmartCast soundbars went on sale.