Justin Timberlake’s old-school fans will be glad to hear that his new, stoned-soul sound has been put on the back-burner for “TKO,” which trails the “The 20/20 Experience Pt 2” (due on September 30). Instead, Timbaland serves up a stuttering hip-hop beat, over which a broken-hearted Timberlake sings his sadness through some slightly cliched boxing analogies. It’s solid stuff but we all know that JT can do better than this.