The music documentary — the authorized oral-history-with-archival-footage style essentially invented by VH1’s “Behind the Music” in the 1990s — is currently in an indulgent and expansive era… its progressive-rock phase, if you will. In 2017 alone, music fans have been clobbered by overstuffed documentaries like “Clive Davis: The Soundtrack of Our Lives” (123 minutes), the Sean “Puff Daddy” Combs/Bad Boy Records documentary “Can’t Stop Won’t Stop” (a long 80 minutes) and even Lizzie Goodman’s sprawling book about the early 2000s New York City rock scene, “Meet Me in the Bathroom,” which exceeds 500 pages. (We won’t include Jay-Z and Beyonce’s real-life, multi-platform reality show, which is playing out in real time.)

All three tackle their respective histories with a combination of refreshing honesty and a sometimes inflated sense of self-importance — yet each must also function as entertainment, and how skillfully they incorporate drama largely determines how successful they are. “Soundtrack” uses the drama of Davis’ rises and falls to hammer home his indisputable starmaking abilities (along with a seeming obsession to prove that he was right about virtually everything). “Can’t Stop” utilizes the run-up to a 2016 Bad Boy 20th anniversary concert to revisit Combs’ and the label’s past and to provide a reality-TV-style storyline. And the doorstop-sized “Bathroom” has struck a resounding (power) chord not only because it tells the entertaining story of the Strokes, the Yeah Yeah Yeahs, LCD Soundsystem and others, but also because its recurring misspent-youth-in-New-York-surviving-on-ramen storyline is so similar to (and/or peripherally touches on) those of its audience.

Dr. Dre and Jimmy Iovine — both veteran music producers, executives and cofounders of Beats by Dre — never do anything by half, and “The Defiant Ones,” the four-part HBO documentary series on their lives, careers and partnership that airs nightly Sunday through Wednesday, arrives with all the subtlety of an Apple product launch and doubles down on this rock-doc format. Actually, it feels more like it quadruples down, because at four-and-a-half hours, this comprehensive series examines two indisputably forceful, fascinating, innovative and important characters (and the people and events around them) with a level of detail more suited to a completist study of the Great Depression, the Civil War or The Bible.

Its Tolstoyan length aside, this series, directed by Allen Hughes, does not lack drama or star power. The roughly chronological storyline follows the two principals, alternating between 1960s Brooklyn and 1970s Compton, progressing to their respective rises as record producers (Iovine with John Lennon, Bruce Springsteen, Patti Smith and Stevie Nicks; Dre with N.W.A, other acts on the Ruthless label and his own solo career). The many talking heads include the principals along with collaborators Springsteen, Bono, Ice Cube, Eminem, Combs, Snoop Dogg, Patti Smith and Iovine’s former paramour Nicks, as well as family members and spouses, who are interviewed in a variety of beachfront, poolside and other tastefully palatial settings. (There is also an unusually frequent use of reaction shots, whereby interviewees are seen sitting silently, apparently reacting to quotes or voiceovers.)

The drama comes from the principals and their stories: their successes and failures; their creative brilliance, focus and ferocious drive; their odd-couple partnership (Eminem says, “Jimmy is the levitator, Dre is the innovator”); their willingness to walk away from lucrative enterprises they built from the ground up (Iovine’s record production and label, Interscope; Dre from N.W.A and Ruthless, and later Death Row Records); and in particular Dre’s tragic losses, including his brother, his son and his once-deep bond with N.W.A and Ruthless Records cofounder, the late Eazy-E. Much of this takes place against a backdrop that includes the rise of N.W.A and gangsta rap, the 1992 Los Angeles riots, the exponential growth of the music industry in the 1980s and 1990s and its dramatic, Napster-enabled fall in the 2000s, followed by its Apple-enabled rebirth — which climaxes with Apple’s $3 billion 2014 acquisition of Beats by Dre (an event that is used, rather awkwardly, as a framing device for the documentary).

Format-wise, the Dre/Iovine alternating storylines are generally effective, but it’s in allowing one of the subjects to have his own space that yield the most revealing moments. One such highlight is the humility exhibited by Dre in describing some of his angrier formative years as a rap upstart. There’s a palpable sense of remorse in the mogul’s recounting of those days — particularly with regard to his drunken 1991 assault on TV host Dee Barnes, which was completely omitted (to considerable criticism) from the 2015 N.W.A biopic “Straight Outta Compton” and for which he apologizes at length here, although without mentioning her by name.

Yet the most compelling segment of the series — Episode 3: The 1990s — requires no injection of drama. The two principals meet and agree to join forces, and Iovine’s fast-rising Interscope extracts Dre from his contracts with Ruthless Records; Eazy had sided with financial partner Jerry Heller against Dre in an ugly feud that played out publicly in music videos and on vinyl as well as in the press. At the same time, the ominous 275-pound figure of Death Row Records founder Suge Knight enters the picture.

But the astronomical success of Interscope and Dre’s classic 1992 solo debut “The Chronic” is marred by concurrent events like the L.A. riots, the government’s crusade against gangsta rap, and the corporate civil war that takes place inside Interscope parent company Time Warner. The latter conflict works out beautifully for Iovine and Dre — Interscope is allowed to leave Time Warner and leaps immediately to competitor MCA, where it continues to thrive — but shortly thereafter, Knight’s gang connections and violent tendencies lead directly to the East Coast-West Coast rap war that kills both Tupac Shakur (a Death Row/Interscope recording artist and Dre collaborator) and Notorious B.I.G. Dre and Iovine are badly scarred by the experience, but their success continues as Dre’s “G-Funk” production becomes the soundtrack for a generation and Interscope becomes one of the most successful labels in history, with controversy magnets like Nine Inch Nails and Marilyn Manson as well more pop-leaning artists like No Doubt and Bush.

The fourth and final episode begins with the arrival of Napster, which Iovine immediately sees as the crippling blow to the industry that it quickly becomes. And like virtually everyone else who has continued to thrive in the music business in the years since, he and Dre find another revenue stream: Beats by Dre and its designer headphones and portable speakers. This segment covers the rise of digital music and gives Apple’s Steve Jobs the same rock-star treatment it earlier devoted to Springsteen and Tupac and Eminem. We see Iovine’s relentless drive in high gear as he forces the headphones into photo opps with virtually every artist he comes near — to their annoyance and inevitable submission — and the series concludes with the principals taking a long and self-satisfied look back and forward.

“The Defiant Ones” tells a compelling story and tells it effectively and well, but its bloated length is a bit hard to justify. Sure, the footage is fascinating, but do we really need to see two full minutes of Iovine and Dre testing out Beats speakers in an SUV — does anyone? — or hear the rose-colored soliloquys to wives and family members and multiple descriptions of the principals’ workaholic habits and relentless drive? For all its strengths, what “The Defiant Ones” really needs is the equivalent of a 2-disc distillation of a 10-CD boxed set. As it is, this is a directors’ cut that runs the risk of more-casual music fans tuning out.