Why did it take decades for R. Kelly to make a disco record? His pristine, emotive vocals and graceful productions would seem a natural fit for the heyday of roller skates and gold lamé — not to mention his lyrical randiness. And that's certainly not a bad thing. On "Write Me Back," his second consecutive album to explore incandescent old-soul sounds, he might have made the best grown-man dance record of the year. Nokia Theatre, 777 Chick Hearn Court, L.A. 8 p.m. Fri.-Sat. $49.50-$125. nokiatheatre.com.