Peeking behind the curtain is almost always a letdown. Most musicians will tell you that while being on stage is exhilarating, the other 22 hours of the day are an endless series of sound checks, infighting and stinky bus rides.

“Vinyl,” Martin Scorsese’s attempt to capture the 1970s rock vibe, tried pumping up the volume by incorporating a murder; “Empire” tossed in everything else.

“Sex&Drugs&Rock&Roll” and “Roadies” offer their own takes with sharply different results.

I was a big fan of Denis Leary’s narcissistic characters in “The Job” and “Rescue Me,” but his fallen star in “Sex&Drugs,” which he co-created, seems like one ego trip too many. In Thursday’s second-season premiere, Leary’s Johnny Rock is determined to make a comeback — as long as the game plan consists of logging more time in the bedroom than the rehearsal hall.

Whether his band is any good or not is impossible to tell since the series rarely allows us to see the gang in action, focusing instead on their soft-core-porn lifestyles. The most notable participant is Rock’s daughter, who has shacked up with a much older bandmate and is starting to explore lesbian liaisons, with Dad cheering from the sideline.

There’s a potentially worthwhile storyline involving Ava (Elaine Hendrix), a backup singer finally ready to take center stage. A scene in the third episode in which we watch her slowly win over a rough bar crowd is a highlight.

“Roadies,” which premieres Sunday, barely acknowledges the performers, focusing instead on the crew that supports the fictional Staton-House Band. Tour managers Bill (Luke Wilson) and Shelli (Carla Gugino) set the tone by constantly whining about their impossible workload, without actually ever doing much more than stroking each other’s bruised egos. Much of the behind-the-scenes “action” is seen through the eyes of rigger Kelly Ann (Imogen Poots), who contemplates giving up film school so she can fulfill every young girl’s dreams of operating a teleprompter.

The characters may be using their downtime to scribble out sanctimonious, romantic speeches about the importance of following your heart. “Maybe the brand is not a brand,” says Kelly Ann, standing up to a British-born money manager who swears his allegiance to the music of “The Munford Sons.” “Maybe it’s a feeling.”

Do not cue the orchestra.

The blame or credit for those monologues belongs to their eternally optimistic creator Cameron Crowe, who could use a comeback of his own after a string of big-screen letdowns.

But Crowe, the former Rolling Stone writer who made “Almost Famous,” retains enough insight about the business to sprinkle in some nice touches: the battle for a prime bunk on the bus; the way a stalker maneuvers her way into a dressing room; the audio engineer who threatens bodily injury to anyone who dares sit in her chair. There’s also a killer soundtrack that includes the Replacements’ “Talent Show” and Bob Dylan’s original version of “Tangled Up in Blue.”

The characters in “Roadies” aren’t living the glamorous life — and that’s just fine as long as Crowe and his producing partners, who include J.J. Abrams and “My So-Called Life” creator Winnie Holzman, keep the spotlight on these fragile, but plucky characters from the shadows.

It may not be rock ’n’ roll — but we like it. Twitter: @nealjustin