Nubart Team

IT Development

(Article written by humans)

April 25, 2023

How we make Nubart PWA audioguides accessible

Museums strive to be places that can be enjoyed by all citizens, including those with physical or cognitive disabilities. That's why at Nubart we've made every effort to make our digital audio guides accessible to everyone. We tell you how.

Nubart's blog - accessible digital audioguides

Accessibility of digital audio tours for the visually impaired

The concern to facilitate visits to museums for blind people goes back a long way: in 1913 John Alfred Charlton Deas, former curator of the Sunderland Museum, invited the children of the Sunderland Council Blind School to see some of the collections of the Sunderland Museum through their hands. The success of this initiative encouraged him to extend this type of visit to blind adults.

Blind children from Sunderland Council Blind School touching a walrus at Sunderland Museum
Blind children at Sunderland Museum - Tyne & Wear Archives & Museums

In a museum, accessibility for the blind does not depend solely on audio guides. Braille labeling and tactile touchpoints that reproduce the object and make it visible with the fingertips are a fundamental element for inclusion.

Touchpoint at the Gruuthusemuseum, Bruges
Touchpoint at the Gruuthusemuseum, Bruges (Belgium) - Photo: Nubart

However, audio guides play a key role in adding value to a blind person's visit by appealing to the sense of hearing rather than the sense of sight. If the museum does not have tactile stations, the audio guide is likely to be the only source of information available to a blind person about the work on display.

Programming an accessible CMS

Modern smartphones come standard with very useful applications for the visually impaired: TalkBack for Android and VoiceOver for iPhones. They are gesture-based screen readers that allow you to hear a description of everything on the cell phone, from the battery level to the caller's name. There is a consensus that VoiceOver is better than TalkBack, so iPhones are currently more widely used by blind people than Android.

Nubart audio guides do not use apps, but open directly in the browser of the visitor's mobile phone. Technically, they are a PWA. In order for them to interact with either TalkBack or VoiceOver, our IT team programmed the CMS that organizes the digital content in universal design. As a result, the interface of our audio guides is very responsive to use by visually impaired users. To this end, the necessary labels have been implemented so that the artificial voice can correctly indicate to the user what each interface is for and what actions are triggered by clicking on it.

We have completed this work by conducting several tests with blind people to test and validate the inclusivity of our audio guides.

Finger-detectable QR code

PWA audio guides are usually accessed through a QR code, so it was important to address the accessibility of these codes. A blind person can perfectly well scan a QR code with their mobile camera as long as they know where they are and can point to the indicated location.

For example, the Austrian Parliament has solved this problem by placing several embossed QR codes on the walls next to each point of interest, allowing them to be located by touch.

Following the same principle, the QR codes on the Nubart audioguide cards are also printed with a slight relief so that visually impaired visitors can identify them with their fingertips. As the cards are carried in the visitor's hand and a single QR code leads to all the contents, access to the audio guide is particularly easy and unobtrusive.

QR code printed in relief to facilitate accessibility for blind people in Nubart audio guides.

Audio descriptions of the exhibits

In a truly accessible audio guide, it is necessary to include a track with the audio description of the exhibit, which allows blind people to imagine and mentally reconstruct the object before listening to the conventional explanation provided by the audio guide.

In Nubart, "audio description" is easily accessed from the language menu.

Accessibility of videos shown on museum screens

The principle of audio description for the blind also applies to videos: a truly accessible museum will provide a soundtrack describing the action shown on its screens.

This can be a problem because videos usually have only one audio output. If a museum wants to offer a video in multiple languages, including audio description, it usually needs to provide a set of headphones for each language. Not only do public-use headphones present a hygiene problem, but it can be difficult for a blind person to identify which headphone contains the audio description.

Video station with sound in a Berlin museum
Video station with sound in a Berlin museum - Photo: Nubart

Nubart has patented an innovative technology for this purpose, Nubart Sync.

Nubart Sync makes it possible to pair a video with a perfectly synchronized soundtrack in any language, including audio descriptions for the blind or plain language tracks for the cognitively impaired. Nubart Sync differs from other more complex and expensive technologies in that the soundtrack is synchronized with the video only over the Internet.

Nubart has used Nubart Sync to implement an accessible audio guide at the Caesarea Port Visitor Center in Israel.

Accessibility for deaf and hard-of-hearing people

As a general rule, providing sound in a museum via a smartphone is a much better option for deaf people than, for example, projecting sound with a loudspeaker in the room or offering audio guide devices that are not enabled. That's because today almost any hearing impaired visitor already has a smartphone compatible with a hearing aid (M3 or M4 rating) or with an audio induction loop (T3 or T4 rating).

There are two ways to provide access to content for the hearing impaired: signoguides (video tracks in sign language) or textual transcriptions. Both options have their advantages and disadvantages. Ideally, both sign language and transcripts should be implemented to ensure maximum accessibility for the deaf.


If you choose a sign guide, Nubart adds this option to the language menu: Videos made by a professional sign interpreter replace the audio tracks.

Problem of signoguides:

  • Sign languages differ, both in lexicon (set of signs or gestures) and in grammar: Spanish sign language is not the same as English, for example. There are even differences between British and American English. The British use the bimanual alphabet, communicating with both hands, while Americans use only one hand. Although there is an International Sign System (ISS), it is not precise enough to provide a reliable translation of the text. It is therefore recommended that two sign guides are used: one in the main language of the audio guide and one in International Sign Language.

  • The inclusion of signoguides will not provide accessibility for all deaf visitors: of the 360 million people with hearing loss in the world according to the WHO, only about 70 million use sign language as their first language or mother tongue.

  • The production of signoguides requires specialized professionals and is costly.

  • The signoguides are displayed in video format. As they are very large files, it is often not feasible to preload them in offline mode in places with poor coverage. However, if the museum has Wifi throughout its facilities or good mobile data coverage, they can work perfectly well in streaming.

Transcriptions: a simple complement or alternative

Nubart allows access to the transcription of the audio guide text through a button located next to each track that opens an overlay window with the text. This option is perfectly compatible with offline preloading in case the museum has coverage problems.

Transcripts are perhaps the least expensive accessibility option to implement. However, they are far from the solution to all accessibility problems for the hearing impaired.

Problems with text for the deaf:

  • The prelingually deaf (those who lose their hearing before language acquisition) find learning to read and write very challenging. Although they can learn to copy letters and identify them with pictures, they cannot associate the spelling of letters with the sound elements of speech. Therefore, not all deaf people can read fluently and the incorporation of transcription will not meet the needs of the entire group.

Captioning the videos

Similar to transcribing audio tracks, captioning helps hearing-impaired viewers understand the audio information in a video.

Here is a video summarizing Nubart's applications for accessibility:

Whatever your situation is, ask us. At Nubart we will analyze your case and give you a quote tailored to your needs.