Final notes from music legends Berry and Campbell

How should a legend be remembered? And whose decision should that be?

These are a couple of the complicated questions raised by new albums out recently from Chuck Berry and Glen Campbell, two important musical figures with long legacies to protect.

“Chuck,” the first studio record in nearly four decades by one of the architects of rock ’n’ roll, follows Berry’s death in March at age 90, while Campbell’s “Adios” comes as the 81-year-old pop-country star is in the latter stages of Alzheimer’s disease.

Both albums are being presented as final statements, yet each has its own ideas about what that means.

By most accounts, “Chuck” wasn’t designed as a posthumous release. When Berry announced in the fall that he’d completed the record — a comically belated follow-up to 1979’s “Rock It” — the singer’s representatives promised to reveal further information about “other Berry-related events.” Such language suggested he might support the album by performing somewhere other than Blueberry Hill, the club in his native St. Louis where he held down a regular gig for years.

If that’s what he was planning, it was to the album’s benefit. More than an attempt to sum up his monumental career — beginning with the foundational late-’50s singles, including “Roll Over Beethoven” and “Johnny B. Goode,” that inspired the Beatles and the Rolling Stones — “Chuck” feels like something Berry banged out in a weekend to get people talking about him again.

The songs are full of familiar riffs and phrases; the playing, by a band featuring his son Charles Berry Jr. on guitar and his daughter Ingrid on harmonica, is loose and scrappy.

Yes, there are acknowledgments of the singer’s vaunted position — namely, “Lady B. Goode,” a kind of sequel to his signature hit sung from the perspective of Johnny’s “little teen queen” from New Orleans. And inheritors such as Gary Clark Jr. and Tom Morello show up to pay their respects.

But you can hardly hear those guys, which is part of what gives “Chuck” its low-key charm. Even when he starts flipping through the Great American Songbook with a shuffling take on “You Go to My Head,” Berry doesn’t make a big deal out of it the way many respect-hungry veterans would. And that actually makes the album a fitting capstone for an artist who rarely appeared to be working as hard as he was.

“Adios” is a very different animal, as indeed Campbell in his heyday was from Berry. Billed as a collection of beloved tunes he never got around to recording in the late ’60s and ’70s — when songs like “Gentle on My Mind” and “Rhinestone Cowboy” were helping to take country music into the pop mainstream — the album is the latest in a series of explicit farewell gestures that began with 2011’s “Ghost on the Canvas.”

That record, released shortly after Campbell announced he had Alzheimer’s, was intended to be his last. But a tour went better than expected, which led to “See You There,” a 2013 set with new recordings of Campbell’s old hits, as well as an acclaimed documentary, “Glen Campbell: I’ll Be Me,” charting the singer’s slow mental decline in brutal detail. (“I’m Not Gonna Miss You,” an Oscar-nominated original song from the movie, is either a grotesquerie or an act of bravery.)

Now there’s “Adios,” which as the title suggests is constructed around the immovable fact of Campbell’s looming mortality. Among the selections are Willie Nelson’s “Funny How Time Slips Away,” Roger Miller’s “Am I All Alone” and the title track by Campbell’s go-to songwriter, Jimmy Webb.

Like Berry on “Chuck,” the singer is accompanied by players who include some of his children. And the album has celebrity cameos from Nelson and Vince Gill.

Here, though, those friends are featured more prominently than those on Berry’s album, and their presence (along with the generally sluggish tempos) has the effect of making Campbell seem frail by comparison — frailer than he used to be and frailer than Berry was at the end of his life.

Portraying the weakness brought on by age is a worthy artistic approach, of course, one Johnny Cash famously took for the handful of albums he made with producer Rick Rubin in the years before Cash died in 2003. But the Man in Black was drawing out themes he’d handled more lightly for decades; the idea of being beat up was in keeping with Cash’s overall artistic project, whereas it’s hard to find the connection between “Adios” and the even-keeled polish of Campbell’s best-known work.