Van Morrison's just-released album "Keep It Simple" hinges on various roots music forms -- blues, folk, country and the occasional gospel -- and if you're going to limit your U.S. tour to three public shows and a South by Southwest showcase, then Nashville's Ryman Auditorium, with its historic ties to the Grand Ole Opry, is a strong symbolic location to underscore the premise.

Two years ago, touring behind his country album "Pay the Devil," Morrison gave a stellar, emotional performance at the Wiltern in Los Angeles, but on this evening, the emotions were much more subtle -- unfortunately, so nuanced that much of the night turned into a mellow, mildly satisfying affair.

Dressed in his typical black suit, black hat and sunglasses, Morrison led the band through a 90-minute rendition that set aside, with one exception, the most familiar elements of his catalog, devoting at least half of the performance to "Simple." He fueled every song with his trademark ad-libs: throaty slurred phrases, scat vamps and compulsively repeated words.

It worked at times, particularly when several songs faded to low volume and he punctuated the air with staccato shouts. But mostly, the lines felt like filler, less inspired than required.CM8ShowAd("Middle2");The band fared much better, each player weaving lyrical solos on top of his or her predecessor's work with taste and fluidity. Their pass-around solos, tossed out by Morrison with small, undramatic gestures, were somewhat reminiscent of Bob Wills' Western swing shows, a particularly interesting comparison given an unexpected twist in the staging for the program.

Morrison called out the crew early to move the drums from the back of the stage to a more intimate location; Ryman legend has it that in Wills' 1944 debut on the Opry, which did not allow drums, he convinced management to allow drummer Monte Mountjoy to play behind a curtain, only to pull the kit onstage at the last minute.

Rather appropriately, Morrison's one truly inspired section came when he played tribute to the Opry, belting a unique version of late member Don Gibson's "I Can't Stop Loving You." His roller-coaster vocal slides and a shuddering fiddle solo brought deserved applause.

He picked up an even bigger response by closing the night with "Gloria." It was hardly a transcendent version, but garage rock at least stayed with the theme: It doesn't get much simpler than that.