There are two ways to take My Morning Jacket's fourth album, "Z" -- as sacrilege or as a big improvement. Beginning as the sort of alt-rock band that owed more to Neil Young than to Sonic Youth, MMJ made music that was appealingly unfussy but sometimes drably ordinary. Neither of those qualities endures on "Z," which was co-produced by singer-songwriter Jim James and Brit-rock maven John Leckie. The album boosts the Louisville group's pop quotient by expanding the role of keyboards, adding lite-soul backing vocals and emphasizing sweeping, falsetto-driven choruses.

"Z" does include some more rustic moments, including a few jam-band asides and one song, "Into the Woods," whose wheezing-organ waltz recalls the first era of down-home rock about 35 years ago. But the keyboard riffs, rock-operatic arrangements and yearning refrains of "Wordless Chorus" and "Gideon" are closer to the styles of such theatrical rockers as David Bowie, Bruce Springsteen and U2. Even songs that have a lighter touch, such as the Ventures-go-reggae "Off the Record" or Del Shannon-like "Anytime," could hardly be described as straightforward. "Z" is a multi-layered studio confection, overdone in places but loaded with hooks. Purists may hate the disc, but it could reach the larger audience that doesn't mind taking its alt-rock with lots of sugar and a bit of corn.

-- Mark Jenkins

Appearing Monday at the 9:30 club with Kathleen Edwards.