Very cool concept. I think you'll probably even get some good traction with it. Love the "sync" aspect of it that means everyone in a channel is hearing the same thing.
By the way, the fact that you're giving tools to people who listen to a lot of music on YouTube (most people in younger generations do) is solving a major problem. These people currently have few ways of creating playlists in ways that are intuitive to them and geared for music.
If I can offer any constructive criticism it would be to get rid of the Facebook login stuff and just roll your own. Make it easy to connect with Facebook/Twitter/whatever, just don't limit yourself to Facebook users who are willing to connect with you. I made that mistake in a user-generated content product I launched last year and it limited my reach.
By the way, the fact that you're giving tools to people who listen to a lot of music on YouTube (most people in younger generations do) is solving a major problem. These people currently have few ways of creating playlists in ways that are intuitive to them and geared for music.