music in FLDS, well, as you can hear in the flat affect of his voice, no emotion is supposed to be shown, a law of the church. Word "fun" banned. No laughing, no crying, no excitement, no emotion, just "keep sweet".
But how can anyone sing without some emotion?
Here is a prayer service with singing. In my mind, I can imagine that singing is the only time people in FLDS feel some release of their tightly held in emotions!

Jeffs singing prayer service Group singing with piano accompaniment.