Jekyll + Hyde (Southern Ground/John Varvatos Records/Big Machine Label Group/Republic, 2015)

Fans looking for the Zac Brown Band of 2005 won't find it in "Jekyll + Hyde" - there's nothing but an aftertaste of the Georgia group's chicken-fried origins. That might be why the album's name is so appropriate. Fans have gotten to know the country-folk band, but a deviant creeps in on all 16 tracks of its fourth album. And, like the classic story, Hyde stands out as more interesting.

It hits hard, too. The opener, "Beautiful Drug," has an electric-pop sound with a refrain that's catchy and somewhat early-aughts - something meant to be sung while cruising top-down in a 2002 Chrysler Sebring. That leads into "Loving You Easy," a hybrid of neo-disco and folk and an almost Celtic-sounding "Remedy."

There are three standout tracks, and only one of them resembles ZBB's original sound. "Mango Tree" features singer-songwriter Sara Bareilles and what sounds like Michael Buble's big band - it's an old time staple that places listeners in a swing club emceed by Frank Sinatra.

From Astaire and Rogers, the album goes to Marvel and DC. "Heavy is the Head," hard rock that sounds straight from a superhero movie soundtrack or Soundgarden album, and not just because it features Chris Cornell and Brown competing for best Osborne impression.

It's easy to point out the Mr. Hyde parts of the album because they're so different from the group's original sound. But Dr. Jekyll is equally as strong, appearing in the emotional "Dress Blues," a song that pays tribute to the troops without dressing up in red, white and blue. Originally by Jason Isbell, the new version has a higher production quality and keeps the emotion despite tweaking and somewhat dulling the lyrics.

But the most standout lyric is the one that sums up the entire collection. "I have everything I need and nothing that I don't," Brown sings in "Homegrown." There are songs that lag compared to the rest - "Castaway" is fun, but listeners might as well turn on Jimmy Buffet instead - but every single one is quintessential to the collection's theme.

Jekyll would be monotonous without Hyde, and the monster wouldn't exist without the doctor. Without the out-of-place tracks, ZBB's album would be easy to put on the country-rock shelf. But ZBB wouldn't be recording big-band with Bareilles or rock with Soundgarden's frontman without the country that made it famous. The mix might be jarring for fans with country proclivities, but where would be the excitement without a little suspense?