Alone in a darkened, smoky house I hear a creak.
Is it behind me? No, that cupboard’s closed. I’m pretty sure I closed it. Is it from the stairs? Wait, sorry, that’s just the person carrying the smoke machine.
And while a little part of me wonders if the severed scarecrow head staring at me from my right has something to do with the noise, I’m almost certain that’s been put there by the production team to scare me.
Of course, if I control my nerves I know where the noise is really coming from – right in front of me on a small black slab of glass and electronics, where I’m playing a version of this Saturday’s edition of Doctor Who with a special “binaural” mix. Also known as “3D sound”, in practice this means that the audio of the episode has been mixed in a special way that tricks your ears into thinking certain noises are coming from behind, below or above you – perfect for a haunted house story.
"Mike Bartlett’s episode Knock Knock is perfect for 3D sound as it’s set in a creepy house where creaks might kill you!" executive producer Brian Minchin said in a release. "What you can hear, and where it comes from is extremely important. The binaural audio edition enhances the fun and the scares throughout Knock Knock."
After the episode airs normally on TV on Saturday evening this immersive version will be available for people to watch on BBC iPlayer (with headphones – it only works with headphones) alongside the normal episode, but before that I was invited along to the story's filming location in Newport, South Wales for a demonstration of its hair-raising effect.
Once there, I was encouraged to find a spooky location where I could properly appreciate the sound mix alone, so opted for a spare bedroom that I thought was relatively stripped of the random Doctor Who memorabilia that had been scattered by the production team about the place. I only spotted the dismembered scarecrow a minute or so in, so that was a fun surprise.
An example of the binaural sound mix from this week's episode - use headphones to listen to this scene
Anyway, after I got used to my surroundings I can report that this unusual way of watching Doctor Who definitely has its merits. In the scarier scenes the creaks and bangs of the deadly house seem to be happening all around you, creating a more involving version of the action that’s both creepy and great fun to be a part of.
In one memorable scene, where Bill and her besieged housemates hear a scuttle from the room above them, the noise made me reflexively look upwards, the binaural mix and general atmosphere convincing enough to make me feel like I was truly in the thick of things.
Still, there are a few caveats. As the episode continues the 3D sound mix gets a little lost in all the dialogue and action, and by the end (when the slow-burn, atmospheric scares are over) it doesn’t feel that different to a particularly well-mixed surround sound episode.
And it’s definitely not lost on me that the setting to my particular viewing experience helped increase my sense of the binaural mix’s creepy effectiveness (or effective creepiness, depending on your perspective). I was in the house actually used for filming, alone in a dark room stuffed with creepy Doctor Who-themed memorabilia. How could I not be a bit unnerved already?
Other attendees who’d watched in each other’s company mentioned that they found the experience slightly less immersive thanks to the distraction of their friends being near them, so I can only imagine the effect would be weakened even more if you were to watch in a brightly-lit, modern environment surrounded by family and loved ones.
So with that in mind, I have some advice. If you're going to watch this week’s Doctor Who in iPlayer (whether you missed it live or just fancy another watch), try the special binaural version. Find a set of headphones (they don’t even have to be that good, basic pods will work OK), and retreat alone to the darkest, spookiest part of your home that you can find, where you’re least likely to be disturbed.
Once there, press play and enjoy one of Doctor Who’s creepiest episodes in years in a form that makes it even scarier. Oh, and watch out for those creaks – they might just sneak up on you when you least expect them.
Doctor Who: Knock Knock airs on BBC1 on Saturday 6th May at 7.20pm, and will be available on BBC iPlayer in both normal and 3D sound versions after the episode airs