Reggae crooner Gregory Isaacs was once the undisputed “cool ruler” of lover’s rock, and his distinctive nasal voice graced hit after hit from the ’70s to today. It’s simply impossible to spend any amount of time at a reggae dance without hearing such classics as “Night Nurse” or “The Storm.” But time and hard living have taken their toll on the 53-year-old singer, and his output over the last 10 years or so has been less than spectacular. One exception to that was 1995’s Dreaming, produced by the team of Leroy and Dave Heywood (a.k.a. Mafia and Fluxy). On his latest, Open The Door, Isaacs tries to recapture the magic by again teaming with this dynamic duo, but with decidedly mixed results. Some tracks, such as “Forgive Me,” with its evocation of Isaacs’ classic “Storybook Children” and the Prince Buster-inspired “False Evidence” recall better days, yet on too many others here he simply phones it in. What’s worse is that, although his trademark phrasing is still pitch-perfect, his voice is no longer the precision instrument it once was.