There's a new N.E.R.D. album out, so it's best to plan ahead: Carve out some time and be prepared to put in some work. N.E.R.D. albums are not passive things. This is not background dinner music, folks.

The 11-track "No_One Ever Really Dies" by the trio — Pharrell Williams, Chad Hugo and Shay Haley — is equal parts experimental, intriguing, frustrating and captivating.

In other words, very true to its side-project DNA.

Many of the songs don't seem quite finished, and some are completely overcooked. A few switch gears in midstream, as if the band was distracted by something else shiny in the studio. Many of the lyrics are wacky until they get deadly serious.

It's tempting to initially dismiss the whole thing as half-baked — or at least made while really baked. But there's also great richness here, sometimes hiding in the layered swathes of upbeat computer synth, distorted sounds, endless repetition and random electronic shards.

As a testament to Williams' stature, he has attracted Rihanna, Gucci Mane, Wale, Kendrick Lamar, Future, M.I.A., Andre 3000 and Ed Sheeran to make featured appearances, while A$AP Rocky and Mary J. Blige offer backing vocals on "Kites."

Just as he asks plenty from his listeners, his guests are also made to work, not just add luster. So Rihanna raps on the opener "Lemon," and Sheeran is almost unrecognizable in the closing track, the reggae-themed "Lifting You."

In "Voilà," Williams mimics an ’80s computer voice. On "1000," he and Future mock conspicuous consumption in a New Wave style. "ESP" is pretty much fully insane, and "Lightning Fire Magic Prayer" has complete brilliance often lost in the mix.

N.E.R.D. teams up with Lamar and co-writer Frank Ocean on the groovy "Don't Don't Do It!" inspired by fatal police shootings of black men. "How many more of us gotta see the coroner?" Lamar raps. "Slain by the state badge." This is an album that references Voltron and Bentley cars but also notes, "Corporations won't pay for effects they cause."

If most people stumble across "No_One Ever Really Dies" expecting an album of wall-to-wall versions of Williams' hit "Happy," they'll likely be confused. But whoever sticks around and puts in some effort will find little jewels.