Big time partnerships don’t always equal big time success, but they often make for bold ideas.

That was proven most recently by the partnering of rock ‘n’ roll legends Lou Reed and Metallica on “Lulu.”

The partnership produces abrasive sounds and blunt lyrics that make for a headlong trip into the underbelly.

The concept for the album, and many of the songs, dates back years to when Reed was asked to write songs for a production of German playwright Frank Wedekind’s two plays centered on “Lulu.”

Wedekind’s plays, like the album, focused on a young dancer who scales the ranks of German society, only to fall into poverty, prostitution and even an encounter with Jack the Ripper.

Reed’s project was scrapped until Metallica backed Reed at the Rock ‘N’ Roll Hall of Fame 25th anniversary concert in 2009 on a performance of “Sweet Jane.” The group decoded to record together and settled on “Lulu.”

Wedekind’s plays tested the boundaries of what was accepted on the 19th Century stage. Likewise, Reed and Metallica set out to stretch the limits of acceptable content in modern songs, though the result is likely far less shocking today than in 1895.

This is no album for children, youngsters or goody two-shoes.

It’s adult and often explicit. In fact, one motto sited on the band’s website comes from a William Butler Yeats quote: “Sex and death are the only subjects seriously interesting to an adult.”

Most of Reed’s growly vocals are spoken word over Metallica’s power-rock or intermittent drones.

On “Frustration,” Metallica switches between vast guitars and ambient sounds over Reed’s repetitive musings with lyrics like “I wish that I could kill you / but I too love your eyes / I want you as my wife.”

Even before its release, the sound turned away more than a few fans.

When “The View” was released before the album, it attracted a slew of dislikes on Youtube — more than 17,000 dislikes to about 5,000 likes earlier this week.

The response isn’t completely surprising. Often times, the album is filled with harsh sounds and less-than-catchy lyrics.

“I want to see you doubt every meaning you’ve amassed like a fortune. Oh, throw it away,” Reed sings on “The View.”

Youtube isn’t the only way fans expressed distaste. In a recent online report, Reed said Metallica fans threatened to shoot him. That shouldn’t come as any surprise to many fans. Reed’s career is built on stretching the limits — just listen to a few minutes of “Metal Machine Music.”

Even in the 1960s when Reed fronted the Velvet Underground — now considered by many a highly influential act — the band raised more than a few eyebrows.

The same can be said of Metallica.

However, it’s likely Metallica fans will reject the sound more than Reed’s fans, who are used to variations in his sound.

Metallica guitarist Kirk Hammett described the groups sound best on their website: “It’s definitely not a Metallica album or a Lou Reed album. It’s something else.”

Sure, both groups bring their styles to the table, and occasionally they collide like opposing magnets. But, at times Metallica’s power and Reed’s mumbling, spoken style blend into some new.

The album ends at it’s best song: “Junior Dad,” which sounds like a solemn, 19-minute epitaph.

Despite the album’s downsides, Reed and Metallica stick to their joint vision — full well knowing they’re going to alienate more than a few fans.

It’s hard not to respect such a bold vision and risk, even though the musicians don’t always hit the bull’s-eye.

“We pushed as far as we possibly could within the realms of reality,” Reed said on the band’s website.