The struggle is real for Katy Perry on her new album

Katy Perry – Witness (Capitol)

She once roared. But now, we'll just call it meowing.

Katy Perry, one of the top voices in contemporary pop over the last decade, limps into her fourth album with a collection of songs that don't have a cohesive feel or message. It's a random hodgepodge of tracks that don't spark or shine; some of the tunes are cute, but most are forgettable.

Witness doesn't offer a fresh, or refreshed, Perry — the only thing new about her is that haircut.

Vocally, she doesn't sound inspired or inspiring. And while Witness isn't expected to be the year's best album, what was expected was some fun, killer pop hits.

Lead single, Chained to the Rhythm, is watered-down reggae pop without any real reggae flavour, and current single, the Nicki Minaj-assisted Swish Swish, is a miss-miss.

Witness is Perry's first album without mega-producer Dr Luke, who is currently at war with pop singer Kesha over sexual abuse claims (he denies her allegations). Max Martin, Dr Luke's former mentor, is still present though, along with big names like Sia, Jeff Bhasker and DJ Mustard.

But none of them come to Perry's rescue. The beginning of Hey Hey Hey sounds like Dark Horse, Perry's last No 1 hit, and the hook echoes Avril Lavigne. Bigger Than Me comes off like a leftover track from her 2013 album, Prism. And the title track is a bore.

Perry finds the right momentum on the dreamy Tsunami, produced by Mike WiLL-Made It; Bon Appetit, chosen as the official second single for mere minutes, is upbeat and catchy; and Power, with little lyrics, is a shining effort thanks to multi-instrumentalist Jack Garratt's layered, experimental sound.

But overall, Witness falls short. The album's songs are almost as awkward as Perry's recent actions, from the weird dancing onstage with rap group Migos to her "joke" about comparing her hair to former US President Barack Obama. It is also the first time Perry is launching an album without a monster hit behind her.

"Swish swish bish/Another one in the basket," she sings. Witness is more like an air-ball.