Berberian Sound Studio (15)

The sound expert has had a rough time of it in the movies. Think of Gene Hackman's professional eavesdropper in The Conversation, stripping down his room – and his life – to a sad shell. Or of John Travolta's sound-effects guy in Blow Out, stumbling on a Chappaquiddick-style conspiracy and thereby sending a loved one to her doom.

Considering the calamitous possibilities of mishearing, and of misinterpretation, the situation of the sound man has been oddly underused in film. The British writer-director Peter Strickland has belatedly spotted its potential and spun from it the intriguing Berberian Sound Studio, half-satire, half-Lynchian nightmare.

Its basis is a fish-out-of-water story. Toby Jones plays Gilderoy, a diffident British sound engineer who arrives at a post-production studio in Italy to help mix a film. The time is the mid-1970s, though we know this only from the clunky analogue sound equipment and the overwhelmingly brown clothes most of the studio technicians and actors wear.

Strickland's camera never so much as peeks outside the cramped confines of Berberian. Gilderoy, whose background is in nature documentaries, has been hired to work on a film called The Equestrian Vortex, which he assumes, reasonably, to be about horses. In fact, it's a low-budget horror flick involving priests, witches, black magic and multiple dismemberings. "Maybe it's best I go home", he says to the stern producer Francesco (Cosimo Fusco), who won't hear of it: he's signed on, he's a pro and he'll damn well do it.

A pro Gilderoy most certainly proves to be. Can he do the sound of a witch being drowned in boiling oil? No problem. Required to fake the sounds of flesh being stabbed and skewered, he goes to town hacking fruit and veg to pieces; for a scene written as "priest pulls witch's hair (hard yank)" he tears the head off a radish.

Of The Equestrian Vortex itself we see only the opening credits, a lurid splash of crimson and black that pays homage to the giallo genre of Italian pulp cinema. Not a frame of the actual movie gets shown, though we are invited to imagine its grisliness from the terrified whispers and screams unleashed by voice-actresses, or the noise of marrow being destroyed in a frenzy of slashing. In a moment of queasy comedy a piece of freshly murdered watermelon is handed to Gilderoy without comment. This stuff is for eating, too.

But it's not just the nature of the film that unnerves Gilderoy – it's the people he's working with. He speaks no Italian for starters. His attempts to claim travel expenses are rebuffed by the studio's spectacularly unhelpful secretary (Tonia Sotiropoulou). Producer Francesco badgers and bullies him. The horror maestro Santini (Antonio Mancino) greets him as "this beautiful, crazy man", which doesn't at all fit what we know of Gilderoy, a quiet, insular type who lives with his mother in Dorking. Indeed, the fond letters she writes him about the birds ("chiffchaffs") in their garden and her sign-offs ("God bless, Mum") are enough to suggest a profound homesickness.

Continental flamboyance is utterly alien to the poor man; you can almost feel him flinch when one of these strapping Italian dudes grabs him in a hug. Toby Jones catches that English reserve wonderfully with his quick nervous smile and air of distraction.

Strickland plays a canny game here. His feature debut, the brilliant Katalin Varga (2009), was a harrowing folk tale of a woman's long-pondered revenge in Romania. Where that film was all about landscape and the outdoors, Berberian Sound Studio is a chamber-piece, set in a Kafkaesque warren of windowless corridors, anterooms and enclosures. The studio is a land unto itself, its ambience entirely mechanical, be it the sprockety whir of the reels, the atmospheric crackle of magnetic tape, the ghostly projection of recorded voices.

For a while the film plays the soundman's uncertainty for laughs. When the producer asks him of a sequence they've just watched – "As you watch the woman do you see a Catholic or a witch?" – Gilderoy pauses for a moment. "I'd rather not get technical", he replies. Yet there is something ominous in the way Gilderoy is sucked into the life of this movie we never see. The scarlet light of silenzio that keeps flashing on comes to seem a collusion on his part, an agreement to hold his tongue as the atrocities unfold on screen. The disconnection between the life of the studio and the life of the film starts to blur.

Yet just when we expect the two to merge, Strickland takes the movie off in a different direction. Gilderoy's head has been thoroughly messed with, but the psychological pay-off is too enigmatic to unpack. Suffice it to say that parallel worlds seem to fold in on each other and news from an English garden starts turning up in an Italian studio. I wonder if I'm alone in feeling a bit disappointed by the final quarter. A set-up rich in possibilities has brought us to the brink, then taken a step sideways into inconclusiveness.

Strickland is plainly not a director who likes to package his stories and tie them up with a bow. It's sometimes a good thing to be confounded by a work of art, which may resonate the more for refusing to yield its secret. It would help, all the same, to feel that there is a secret in there to be yielded.