If you’ve seen the trailer for Whiplash, you’ll know that jazz conductor Terence Fletcher (J. K. Simmons) is not of the ‘accentuate the positive’ school of teaching. To play in his band, the top jazz ensemble at Shaffer Conservatory, means enduring an almost uninterrupted stream of insults and dodging the occasional flying chair. It’s a method designed to sort the boys from the men, and 19-year-old drummer Andrew Neiman (Miles Teller) is determined to meet the challenge.

Whiplash is the second feature film from Damien Chazelle, a Harvard graduate whose first effort, Guy and Madeline on a Park Bench, was a low budget, black-and-white affair, strongly indebted to the Hollywood musical tradition and the French New Wave. While it received nowhere near the kind of exposure that Whiplash has enjoyed, some critics sat up and took notice, Jeannette Catsoulis of The New York Times declaring that the film displayed “style to burn.”

With Whiplash, Chazelle has jettisoned the nostalgic breeziness of his debut for psychological seriousness. His ‘style to burn’, however, remains intact. Exploiting its musical theme to the fullest, editor Tom Cross has the film zip along at the pace of a bebop record, accenting beats with extreme close-ups of drum sticks, saxophone bells and bass strings. This visual panache is central to the appeal of Whiplash and ensures that for pure entertainment value the film – maybe even the thrilling concert hall climax alone – justifies its ticket price.

The point of Whiplash, though, is not its jazzy aesthetic but its monumental ego clash, from which we are apparently meant to draw lessons about the dangers of pushing oneself to extremes. If the end result is not quite the devastating character study to which it aspires, the fault can hardly be said to lie with Simmons and Teller, both inspired casting choices. Many will recognise Simmons as the disagreeable newspaper editor J. J. Jameson from Sam Raimi’s Spider-Man trilogy, and while both parts give Simmons some good barking to do, the differences in body language are telling. Where Jameson spent most of his time behind a desk, Fletcher is nearly always on his feet, prowling, stalking or striding around the rehearsal room in case there’s any doubt who’s boss. Teller, meanwhile, plays young Neiman with impressive restraint, masking his ravenous ambition with a deceptively ordinary demeanour.

This talent is put to dubious use in the rehearsal scenes which dominate the film. When Neiman struggles to play the absurdly fast double-time swing patterns demanded by Fletcher, tears are shed, blood is spilled and Fletcher unleashes his inner Drill Sergeant, offering homophobic epithets aplenty. It’s not at all clear how Chazelle wants us to react to Fletcher’s venom, and herein lies Whiplash’s fatal flaw. On the one hand, the conductor’s outlandish pejoratives are too preposterous to be taken seriously. (To a trumpeter who pre-empts his cue: “It’s not your boyfriend’s dick, don’t come early.”) Equally, if taken as comedy, Fletcher comes across as a poor relation of Malcolm Tucker’s, and the zingers lose their zing with overuse. Falling between these two stools, the characterisation of Fletcher ends up lacking basic credibility, and the audience is distracted from the drama by the nagging question, ‘Would anyone really put up with this jazz fascist for a single rehearsal?’

Consequently it’s a relief when, in a jazz club scene, we are finally allowed to observe Fletcher operate at a lower volume, not shouting this time but calmly explaining the rationale behind his unusually rigorous regime. Similarly, the scene in which Neiman dumps his girlfriend (Melissa Benoist) with robotic calm comes as another welcome break from the macho histrionics. It’s agonising to see Chazelle misfire like this, because if he had just reigned in the character of Fletcher a touch, gradually teasing out his psychotic tendencies rather than unloading them on the viewer like a pile of bricks, Whiplash would be all the more riveting. As it is, melodrama trumps menace.

That’s not to say Chazelle hasn’t pulled off a remarkable feat. Did anyone guess that 2014 would be the year a medium-budget drama about jazz musicians directed by a twentysomething pulled in both box office dollars and reviewers’ stars? Chazelle has essentially revived a sub-genre of yesteryear. He has said that with his next film he intends to do the same for the classic ‘Fred and Ginger-style’ musical. If he is to succeed he needs to prove that his ‘style to burn’ is matched by characters that convince.