For a man who took music into hitherto uncharted realms, the first feature-length documentary about jazz saxophonist John Coltrane is surprisingly straight. That doesn’t mean it isn’t good. It is informative and, at times, touching. It’s just odd that its tune is so predictable.

Mixing concert footage, home movies and photographs with talking head interviews from colleagues, inspired younger musicians and a few well-chosen commentators, “Chasing Trane: The John Coltrane Documentary” gives you all the biographical data you need, plus testimonials swearing he was one of the great geniuses of recent history.

If you are a Coltrane fan, you’ll be nodding in agreement. If you are new to the great instrumentalist’s work, you may find yourself shouting “show, don’t tell!” Frustratingly, director John Scheinfeld has a tendency to cut just when the music starts to wail.

He does, however, have an ace up his sleeve. Coltrane gave no television or radio interviews before he died in 1967 at the age of 40. Scheinfeld has smartly hired Denzel Washington to “play” Coltrane in voice-over, reading from print interviews and liner notes. He brings outstanding gravitas to stories of his upbringing in North Carolina, his teen years in Philadelphia and his apprenticeship in Dizzy Gillespie’s big band. Then comes the pivotal year of 1957 when he is dumped from Miles Davis’ Quintet due to a drug addiction.

“Chasing Trane” has many remarkable personalities explaining their admiration, including former President Bill Clinton. (Yeah, remember he played the sax?) POTUS 42 has some acute insights, however, as does the always emotional rock guitarist Carlos Santana and the public intellectual/wordsmith Dr. Cornel West. West may be the one to put some at ease when he admits that Coltrane’s later free-jazz work is, quite frankly, not something he listens to all that often.

But before Coltrane could become an iconoclast, he had to tackle his masterpiece, and “Chasing Trane” gives the 1965 album “A Love Supreme” its due as a work of intense spiritual cleansing.

Dipping in and out of Coltrane’s heralded “sheets of sound” may not convince you, but when elderly colleagues like Wayne Shorter, Sonny Rollins, Jimmy Heath and Benny Golson recollect with such fondness, the film does plenty of convincing. Luckily, the music is all still available for further review.