** 1/2 MATCHBOX TWENTY, “Mad Season by Matchbox Twenty”, Atlantic

Maybe Rob Thomas learned something about the Groove when he sang on Santana’s “Smooth.” The new album by his group Matchbox Twenty (which plays the Wilshire Ebell Theatre on June 6) scraps most of the regimented rock riffing that framed its 1996 hit debut in favor of a looser, more fluid instrumental concept.

The idea seems to be to free Thomas up to show his stuff as a soulful shaman with instinctive, intuitive vocal moves. It’s the Van Morrison model, but where the originator’s passions were grand and his revelations painfully intimate, Thomas--for all his vocal suppleness and agile phrasing--doesn’t get far beneath the surface. He’s testy when you want him to be enraged, annoyed when he should be mortally wounded.

That emotional tepidness reflects the aims of Matchbox Twenty’s music, which seems designed to be as tasteful and neutral as possible while retaining a roots-moderne credibility. There’s something to be said for sounding good, and a succession of ear-grabbing hooks and melodies makes “Mad Season” as catchy as it is crotchety.

*

Albums are rated on a scale of one star (poor), two stars (fair), three stars (good) and four stars (excellent). The albums will be in stores on Tuesday.