» The Difference Engine

The Difference Engine is Talking Birds' discreet new tool for making events and performance accessible to partially-sighted, deaf or hard of hearing audience members by delivering captioning or audio description direct to their mobile device.

There is now a Difference Engine app available for beta-testing (although it can only be fully tested during a show where the system is running). If you have an Android device, you can download the open beta version of the app via this link: Android App via Google Play If you have an iOS (Apple) device you can download the app from the App Store.

» Comments from user-testers

"This sort of thing would ordinarily be off limits to a deaf or hard of hearing person as you just wouldn’t be able to following anything that was being said. Especially because performances were happening in various parts of the venue as opposed to a fixed stage...It worked really well and a key part of this for me is that it’s something that is relativity inexpensive to run as it’s software running from a laptop! I really think this has a lot of potential and could bring subtitles to ANY event with very little expense to the organisers." [audience blogpost]

"I followed brilliantly because...within Talking Birds someone had created a new way of captioning that I honestly think, with some backing, could be the next big thing...I was also seriously impressed that a small bunch of people in a low-budget performing arts group saw it as important that their show was accessible to all and deemed it necessary to devise and implement a method to make it possible." [The Hearing Times]

"I had given up going to the theatre and live shows because of the isolation it creates when you cannot hear, particularly when the audience is laughing at something said on stage. So thank you for making this experience more inclusive." [audience feedback by email]

» Beta-testing

Thanks to investment from the Paul Hamlyn Foundation and the Esmee Fairbairn Foundation, the second version of The Difference Engine is currently in beta-testing with a number of arts organisations across the country. We will aim to publicise all the events at which it is being tested so that you can go and test it yourself (and see lots more art into the bargain!) and we'd be really interested to get any feedback from you as to how you found the system as a user.

The Difference Engine App enables captions to be delivered to mobile devices during performances and events which are using the Difference Engine system. Captions are delivered using a Wireless Local Area Network, so the Current Event and System Feedback options will only work when your device is connected to a Difference Engine network, at a performance or event. (The system will normally be active at least 20 minutes before an event begins.)

More details to follow soon. If you would be interested in helping to user-test the next version of the Difference Engine, please get in touch.

» Donate to the Difference Engine

We are currently fundraising to develop the prototype system into a more robust and shareable form. Every bit of spare change helps! If you could donate towards this development, you can do this via the paypal button below. Thank you, we really appreciate your support.

» Credits

The Difference Engine was funded to prototype stage by Arts Council England West Midlands' Digital Content Development fund and a subsequent Grants for the Arts award. See how it works here: [short promo video]. The original prototype was programmed by James Shuttleworth. The name was borrowed from Charles Babbage, but it seemed kind of appropriate.

» How the Difference Engine came about

This article is the text of a presentation Janet gave at the Digital Content Development showcase event:


Imagine you are a theatre maker and what you like best is to find unusual, unused, unloved, peculiar or beautiful buildings that the public rarely (or never) get into; buildings whose interesting histories, former uses etc are on the brink of slipping from living memory. And you find this beautiful building (see images above) which is all that remains of a 14th Century monastery incongruously nestling amongst ring road flyovers. There is a long cloister downstairs topped by 50m long gallery upstairs, which was originally the monks’ dormitary. The building hasn't been used for a number of years, but you manage to negotiate that you can use it for a month to make a show.

But when you get inside, you find that the lift is broken, the only access to the breath-taking upper floor is a open wooden staircase - and the Disability Discrimination Act has just come onto the statute books... This was the situation Talking Birds found ourselves in in 2002. Luckily a sympathetic and creative Coventry City Council access officer called Phil Woodcock encouraged us to consider the lack of physical access as a creative challenge: how COULD we make it physically accessible for anyone unable to get up the stairs?

The solution was a compromise, but it worked. We made an alternative accessible viewing position (the Juror’s Gallery) in the ground floor cloister and, inspired by CCTV galleries, we positioned various cameras upstairs (giving some views that the upstairs audience wouldn't be able to get) feeding live to a bank of TVs downstairs. In addition to the live feed, there was a bit of pre-recorded material (which the upstairs audience didn't get to see) showing on one of the screens, plus an inventive stereo sound design which panned the sound across the cloister following the action upstairs. We also blocked the actors to appear onstage downstairs when they were offstage upstairs.

This experience taught us valuable lessons on making a venue work for us. We learned that factors of accessibility should influence the choice of a venue (which obviously shouldn't be a problem in a conventional venue); mobility considerations are only one element of making something accessible (we had a BSL interpreter for one performance, but without concurrent audience development, this is not always money best spent); that creative accessibility solutions can produce more interesting work for everyone, whether they have specific access needs or not; that technology provides excellent tools for solving these kinds of problems in its focus on connectivity and joining people up; and that making something more accessible doesn’t have to be expensive.

The standard access solution for theatre captioning uses purpose built LED boxes, which generally work pretty well in large auditoria, but it depends on the theatre and set designs where they end up being placed and how visible this is. We had used a caption box in a previous site-specific production and had found it anomalous and obtrusive in this setting. Audio description is generally transmitted via infra-red, using the same sort of technology as simultaneous translation, except that the audio-describer has to of course try not to speak over the actors, but only in the gaps. We've tried using these systems, but in our experience, it's an unreliabile method of delivering audio description even in an enclosed theatre, impossible in a non-theatre setting. Over the years we've experimented with improvising our own audio description equipment with the various heath robinson bits of kit we've connected up, and although we've mostly made these work, none has yet been a satisfyingly complete solution.


We make our work in all sorts of beautiful and fascinating buildings - and we have a real sense of privilege when we are able to get into these and explore them. They are often partly derelict, or about to be demolished or re-developed, in transition, and part of the reason we work in these sorts of spaces is that we have a drive to share this experience with an audience, to excavate and to share some of the building’s stories in a mediated, fictionalised way.

So if most conventional access solutions don’t work in these rich and interesting contexts, then we have a conundrum. These places, and the desire to explore them is universal - and the shows we make in these spaces are generally conceptually accessible because of how and why they are made. Once you actually think about it, it is fairly obvious how to make a space accessible to someone with mobility problems - but how do you make a piece of work that involves wandering around a former hospital, cattle market or sorting office accessible to those with visual or hearing impariments?

So we asked ourselves: What if everything was made from a standpoint of universal access? What would happen if we reversed the assumption that making a piece of work accessible is (at best) an add-on to the work and (at worst) an artistic inconvenience? What would this mean? What might the creative possibilities of universal access look like? In what ways might these improve the art? In what ways might they improve the experience for ALL audience members? (Imagine making DDA legislation redundant!)

The game-changer, for us, was the iPhone. Once we had all played with a variety of apps, things began to slot into place... We wondered what would happen if we could deliver subtitles and audio description to people’s phones and other mobile devices? What if they could use their own device to tune into the assistive information that they needed? It would be personal and versatile - even bespoke! It would be perfect for all the unusual spaces we make our work in, but could also work in conventional theatre settings - indeed for a multitude of other events and venues. Think of the myriad of other information such a system could deliver...from the mundane (GPS venue location, credits and programme information, background info about the venue or the show, audience reviews etc) to the more revolutionary (audience messages offering crowdsourced interpretation of the show in real time or affecting the direction the performance takes) for example.

Almost as exciting, we had a hunch that such a system could be the point of convergence for Talking Birds' work on universal access and our personal, interactive, digitally-realised web-based strand of work that began in 2002 with Helloland . This would mean, potentially, we could also use what became The Difference Engine as a platform to deliver accessible interactive digital artworks. (Helloland was a series of monthly interactive web-based artworks made to mark Talking Birds' 10th anniversary, which relied on user input to determine its direction - and in many ways performed a lot of the same playful audience development functions now taken by social media).

We weren’t sure though how many (particularly) blind, partially sighted, deaf or hard of hearing people were using smartphones, but a little research suggested that (particularly) iPhones and iPads are revolutionary new tools for exactly these demographics, so we applied to the Digital Content Development fund and were awarded money to prototype the system. We have worked with Coventry University - who built us a simple interface for version 1 of The Difference Engine which basically delivers subtitles and audio files, and receives feedback, from pretty much any wi-fi enabled device. We've had some very positive feedback from people who've user-tested the system alongside our projects "Capsule" (in an empty industrial unit and then at Warwick Arts Centre) and "A City Grown from Words" (in the former sorting office), and we are now fundraising to develop the prototype further.

Text taken from Janet Vaughan's presentation to the Arts Council England West Midlands' Digital Content Development Fund Showcase at The Public in Wolverhampton, Feb 2011.

links to the difference enginelinks to Talking Birds online shoplinks to Fanfare project - commission a bespoke fanfare