All About Technology for Audio Description
On This Page:
This page was originally prepared and maintained through 2023 by Mike Feltman, an AD equipment professional in Raleigh, NC. USA.
Last updated in May 2024 to add LiveVoice as a Wi-Fi solution
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Audio Description 101...What a Difference
Technology Makes
Scene One: My friend who is blind goes to a local live theater
production with me. During the play, he leans over to me and whispers, "Why
is the audience laughing?" I whisper back, "the husband just pantomimed
a choking motion behind his wife's back!".
Scene Two: I go
to the same play with this same friend. As we walk through the lobby,
he stops at the audio description outreach table and picks up a small radio receiver
and ear piece. We go to our seats and while I'm reading the program notes,
he is listening to the pre-show audio described program notes. He leans
over to me and asks, "Did you know this play we're about to see first appeared
on Broadway in 1959 and was written by Howard Linday & Russel Crouse?" The
play starts, and my friend doesn't ask one question during the play...not one.
We are both free to enjoy the play in our own way. Audio description is being
done in both scenarios.
The difference is TECHNOLOGY!
Each technology has its own set of solutions and shortcomings. Here
we provide a brief discussion about each technology and invite you to tell us
more about how your organization uses technology to deliver audio description
and improve the user experience. For users of audio description, we encourage
you to tell us what works for you and what doesn't.
As we become aware of new technology, we'll add the information and links.
We'll do our best to stick to the facts but we'll also share opinions and publish
information from ADP's Discussion List. More information about the discussion
list is found at the bottom of our "About This Web
Site...." page.
Audio Description Technologies
This topic has four subsections...
TV
TV networks broadcast over the airwaves, cable TV or satellite TV. In North
America and Europe additional transmission equipment is used to broadcast an
audio description channel containing the regular audio with the audio description
added. When your TV or your 'set-top' cable box is configured to receive
the audio description channel, you hear both.
The Good News: There are many popular TV series and TV specials
in North America and Europe broadcasting AD.
The Not So Good News: Setting up your TV to receive audio description
can be a daunting task. Different providers use different technologies within
the same country. Technologies are evolving and those technologies used in the
United States and Europe are not standardized.
We Wish We Knew: How networks will exploit the new digital age
capability to have more than one secondary audio track to allow Spanish language,
for example, to have its own audio channel instead of sharing the AD channel.
For more details about technologies used for TVs in the United States see
Accessing Audio Description on Your
TV.
Added April 2019 (with credit to John Paton at
RNIB.org in the UK)
In the UK users talk about “turning on AD” and many are unaware
of how AD actually arrives at their TV. In fact the UK uses two methods of broadcasting
Audio Description, receiver mix and broadcast mix. In receiver mix the AD is
sent on its own as a separate audio channel which is then mixed with the main
audio. This has the advantage that the user can set the respective volumes although
it’s not clear whether everyone is aware of this or how well it’s used. This
technology is used for digital terrestrial service 'Freeview'. In broadcast
mix the AD is sent pre-mixed with the main audio as a secondary audio track
and the receiver just selects which audio channel to play. This is used for
all other broadcast methods in the UK (cable and satellite services). For video
on demand services it is common to just create a new video asset with the broadcast
mix built in. Certain broadcasters started doing this because some devices didn't
cope well with multiple audio tracks. It greatly reduces the complexity while
just requiring more hard drive space and a tweak to the user interface.
In the rest of Europe I think everyone uses broadcast mix but
this is complicated a bit by countries which have more than one official language
such as Belgium and Switzerland. I think in these cases the AD is treated as
a separate language track. They also have the complication of spoken subtitles
to think about.
The Future of AD on TV in the UK and the Rest of
Europe There’s buzz about Next Generation Audio using Object Based
Audio, (NGA using OBA). This would allow the AD to be a set of tagged audio
objects which can be switched on and off. It reduces the bitrate required as
well as adding all the benefits of NGA such as 3D sound and alternative commentaries
on sport. In Europe it’s being talked about as a logical next step although
it requires a lot to happen so we don't know if or when it will happen.
Movies in Theaters
Most new movies have audio description available which can be detected and transmitted
at specially equipped movie theaters. Patrons are loaned a small receiver
and a headset to pick-up the audio description, while they can hear the regular
sound track 'around' the headset. Recently we used a model with the receiver
built into a small headset. On each ear piece is a volume knob. Turn up the
left volume knob to listen to an amplified version of the sound track. Turn
up the right volume knob and listen to the audio description track.
Find out about movie theaters offering
AD...
Find out about companies offering systems
for AD in movie theaters.
The Good News: Most new movies are being released with audio
description available. All movie theaters are now required to provide AD headsets
once they install digital projectors, which most movie theaters have today
The Not So Good News: The equipment on the movie theater side
is expensive so not all movie houses have it. Theater staff may not be well
trained on the setting up and use of the AD receivers, and equipment failures
frequently occur despite a new law addressing these deficiencies.
We Wish We Knew: How to drive down the cost and drive up the
availability.
DVD Players
Although video tapes (VHS) have become a thing of the past, more and more
digital video disks (DVDs) have a user selectable audio description sound track.
No special equipment is required...just a TV or monitor and a DVD player.
Click here to find out which DVDs
in the United States have audio description tracks.
The Good News:
No special equipment other than a TV and DVD player are needed. Over 1000 DVDs are available with audio description.
The Not So Good News: Although more and more DVDs have audio description
tracks, not all of them have it and purchasing DVDs for individual home use
can be expensive. Rentals may not be convenient or may be impossible in
some localities.
Live Performances and Other Events without
Prerecorded Audio Description
...a live audio describer is present
This is only an introduction. If you are using this information
to plan a new system we encourage you to determine how and where your audio
description will be delivered, the needs and preferences of your users, and
your budget before contacting the vendors.
No matter what the venue and no matter whether the audio description source
is live-on-site or pre-recorded, some type of transmitter-receiver technology
is used. In this section we explore 1) what types of technology are available
for performances and events where a live audio describer is present,
and 2) which technology-ies best fit which conditions.
The 'transmitter-receiver'
concept when live audio describers are present....
The audio
describer’s voice is input to the transmitter, the transmitter broadcasts
the audio description to receivers tuned to receive the transmitter's
broadcast and the audio description is heard by the user wearing an earpiece
connected to the receiver.
Transmitters can be permanently installed in venues or they can be small
portable devices not much larger than a deck of cards. Receivers are typically
designed to be hand-held by the user and typically have an on/off/volume control
and an audio output jack for ear-speakers, ear-buds, or ear phones so as not
to disturb others nearby. We see many systems where the transmitters and receivers
are designed, manufactured and serviced by the same provider, but we also see
systems where the transmitter is from one provider and the receivers are compatible
devices from another provider. We know of some systems that rely on the user's
personal cell phones for receivers. In summary, regardless of other factors
there is always a transmitter and always a receiver.
Broadcast technologies (from the transmitter to the receiver)
Transmitter and receiver systems are further defined by
what broadcast technologies they use; radio frequency or infrared. In
radio frequency designs, the describer's voice travels on radio waves. Radio
frequency use is strictly controlled by government agencies, for example, the
Federal Communications Commission (FCC) in the United States and Ofcom in Great
Britain. Radio frequency is further divided into 'bands'. Examples include "Frequency
Modulated" (FM), Wi-Fi, and cell phone networks like '3G' and '4G'. In
infrared designs, the describer's voice travels on light waves undetectable
to the human eye. Within both the radio frequency design and the infrared design,
transmitters and receivers must be tuned (matched) to the same channel to ensure
they can communicate without disrupting and without being disrupted by communications
of other systems. For this reason, designers of systems must first learn about
every venue in which they intend to provide service so they don't accidentally
design/purchase a system that interferes with an existing system at the venue.
Take for example an audio description provider in the south central United States
who purchased a radio frequency system from a well known manufacturer. The AD
provider spoke to only one venue during the initial system design phase and
based on that knowledge chose a radio frequency system with single channel receivers
tuned to 'Channel I' (74.7 MHz within the 72 MHz band). All was well until the
AD provider tried to use the same system in a different venue across town. Unfortunately,
the AD provider assumed the other venue wouldn't be affected by the Channel
I broadcast, however, the other venue was also using Channel I for an existing
remote emergency/alarm system to the local fire station. Lucky for the AD provider
the equipment manufacturer was willing to retune the single channel receivers
to another Channel within the 72 MHz band free of charge.
In general, radio
frequency systems can penetrate walls to some extent. Infrared systems
can have a better sound quality, but are best when in a line-of-sight application.
Infrared systems can't go through walls, but if the installation is more permanent,
infrared repeaters can be installed to circumvent the problem. Users can then
walk around without the annoying 'drop out' sometimes experienced when the antennas
on radio frequency systems go in and out of alignment with the receivers.
Wi-Fi and cell phone broadcasts each have their own place in the mix and although this type of technology is seldom used in 'live audio description' early in 2020 we learned of a system for iPhones and Macs that uses Wi-Fi to deliver live audio description.
In summary, the AD provider must do a great deal of up-front data gathering
to ensure the equipment uses the right technology set to the right frequency.
Live Performances and
Other Events with Prerecorded Audio Description
...no live audio
describer is present
This is only an introduction. If you are using this information
to plan a new system we encourage you to determine how and where your audio
description will be delivered, the needs and preferences of your users, and
your budget before contacting the vendors.
In this section we explore 1) what types of technology are available for
performances and events where the audio description is prerecorded (no live
audio describer present), and 2) which technology-ies best fit which conditions.
Prerecorded audio description dates back decades to handheld receivers distributed
to attendees at museum tours, art exhibits, theme parks etc. The attendees used
earphones to avoid disturbing those around them. In the earliest applications,
the receiver was nothing more than a prerecorded playback device which could
be started and stopped by the attendee as they progressed. The shortcoming was
attendees had to proceed through the tours or exhibit along a predefined path.
No provision was made to take things out of order and these technologies were
not very enabling for attendees who were blind or with low vision. Next, the
technology improved such that at each stop on the tour, exhibit, or park, the
attendee would see (or be told) a particular channel number, tune their receiver
to the channel for that particular stop and listen to the associated audio description.
The next improvement in technology added a small transmitter at each stop to
broadcast its message to the receiver without requiring the attendee to tune
in their receiver to a particular channel. The transmitters and receivers had
to be 'keyed' so only the receivers within close proximity to the described
item would pick up the audio description for the item. These types of systems
are ideal for attendees who were blind or with low vision, no manual entry of
a channel number is required....only that they be close to the item.
Prerecorded audio description technology doesn't stop there. Modern variations
use the attendee's cell phone as the receiver and use of these systems are not
limited to museum tours, art exhibits, theme parks etc. Take for example prerecorded
audio description for live theatre. Companies have begun to produce prerecorded
audio description for use in larger (i.e. big budget) live theater productions
of long running plays or musicals. "Cats" is a good example, and there
are many others. These shows don't change much and can stay for many months
in one venue. The attendee loads an app on their cell phone and attaches earphones
so they do not disturb other patrons around them. The theater installs proprietary
microphones that 'listen' for specific dialog lines. When the line is heard,
the system triggers the audio description associated with that place in the
dialog. A human monitor is assigned to keep track of the audio description and
correct any errors in case a dialog line is missed. Systems like these are not
inexpensive, thus they may not be suitable for smaller local theater where only
one or two performances of any given show are scheduled. However, when the right
show is at the right theater for the right amount of time, the theater can offer
audio description at any performance with no prior restriction or special arrangement,
just like many movie theaters do today. Imagine a future where anyone can load
an app onto their cell phone and hear an audio description track for any movie,
live theater, museum event, art exhibit, or theme park attraction!
We can expect to see hybrid prerecorded audio description systems similar
to the above, but using FM or infrared transmitters and receivers instead of
the attendee's cell phone. But then, if everybody has a cell phone...maybe not.
The variations are just about endless!
Which system is best
It all depends on the specific
environment, portability vs. permanent installation, the nature of the event
being described, and how much the users will be moving around. In general, systems
that work best for live theater won't work best for exhibits and tours and vice-versa.
The Good News: The systems are robust, affordable by many organizations
and well supported.
The Not So Good News: There is no one perfect system. It takes
a lot of research and vendor interaction to determine the best system for a
given environment, and then, it is only 'best' in that environment. What
if your needs change or you want to use the same equipment in a variety of environments?
Compromise is often the only solution.
Audio Description Equipment and Technology (Supplier Links)
We invite providers of audio description equipment and technology to allow us to let our
readers know more about your products.
Disclaimer: Neither the ADP nor the ACB endorse any of these
products or vendors. The list below is meant to help our readers contact
providers of technology. AD environments vary. What works well
for one group in one location may be marginal or totally inadequate for
another group or in another location. We recommend you work with several
vendors to find the best value for your specific application before making
any purchase. Updates to this list are welcome --
contact the webmaster.
This topic has five subsections...
Mask (stenographer) Microphones
Mask (stenographer) microphones fit over a person's mouth so others nearby can not hear
what is being said. These types of microphones are useful for audio describers in live
theatre environments when non-user patrons are seated nearby. When properly
used they do a great job of keeping the non-user patrons from hearing the describer..
Portable Soundproof Booths
- For information on building one, contact Judy Berk at the Cultural Access
Consortium in Boston, 617-357-1864,
Jberk@culturalaccess.org.
- To rent or purchase a portable or fixed Sound Isolation Booth, please
contact Julie H. Setbon at the iProbe Multilingual Solutions, Inc. in New
York City, Tel 212-489-6035,
Email
setbon@iprobesolutions.com
Prerecorded Audio Description in Selected Live Theater, Guides to Parks,
Tours, Events and Broadcast Video
-
Disney
SyncLink/ Disney ACCESS (For guests with sensory disabilities. Uses
the Disney ACCESS™ System, featuring Disney SyncLink™ technology)
-
GalaPro
(Provides audio description of selected live performances via an app on
user's cell phone or tablet.)
-
Penteract, LLC (Provides cell phone apps that can be adapted for use
with pre-recorded museum tours.)
-
Q Media Productions
(Audio description scripts for parks, museums and other venues in the US.
Features 'Orpheo Audio Guide' products.)
-
Sound Associates, Inc, D-Scriptive System (Provides audio description
of selected live performances via proprietary receivers.)
-
Yella Umbrella Ltd. ('Stellar'...a web-based app for adding audio
description to existing video. NOTE: the AD output is synthesized speech)
Solutions and Systems for Audio Description in Movie
Theaters
Transmitters & Receivers for Live Broadcast, Theaters, Museums, Tours,
Parks, etc.
This topic has four subsections.
In each listing M=Manufacturer and S=Supplier.
All System Types
American Loop Systems (S)
29 Silver Hill Road
Suite 100
Milford, MA 01757
(800) GET-LOOP
(800) 955-7204 TTY
Audio Enhancement (S)
14241 South Redwood Road
P.O. Box 2000
Bluffdale, UT 84065
(800) 383-9362
www.audioenhancement.com
Cardinal Sound & Communication (S)
2317 Kansas Avenue
Silver Spring,MD 20910
(800) 964-3496
info@cardinalsound.us
www.cardinalproaudio.com
Centrum Sound (S)
572 LaConner Drive
Sunnyvale, CA 94078
(408) 736-6500
info@centrumsound.com
www.centrumsound.com
Durateq Division of Softeq Development Corp. (S)
(Rugged handheld devices)
1155 Dairy Ashford, Suite 125
Houston, TX 77079
888.552.5001
info@durateq.com
www.durateq.com/
HARC Mercantile, Ltd. (S)
1111 West Centre Avenue
Portage, MI 49024
(800) 445-9968 Voice/TTY
www.harc.com
Hear More (S)
42 Executive Blvd.
Farmingdale, NY 11735
(800) 881-4327 (voice)
(800) 281-3555 (TTY)
www.hearmore.com
HITEC (S)
8160 Madison Avenue
Burr Ridge, IL 60521
(800) 288-8303 voice
(800) 536-8890 TTY
info@hitec.com
www.hitec.com
iProbe Multilingual Solutions, Inc. (S)
FM Systems (72 MHz, 216 MHz), Infrared Devices, Sound Isolation Booths.
(Rental and Sales). Also audio description, captions and SDH subtitles in
English and foreign languages.
273 East 3rd Street, Suite 2W
New York, NY 10156
(212) 489-6035
www.iprobesolutions.com
Listen Technologies Corporation (M)
14912 Heritagecrest Way
Bluffdale, Utah 84065-4818
(800) 330-0891
info@listentech.com
www.listentech.com
NADY Systems Inc. (M)
6701 Shellmond Street
Emeryville, CA 94608
(510) 652-2411
ussales@nady.com
www.nadywireless.com
Potomac Technology (S)
1 Church Street, Suite101
Rockville,MD 20850-4158
(800) 433-2838 voice/TTY
info@potomactech.com
www.potomactech.com
Oticon, Inc. (M) (Formerly Phonic Ear, now under "FrontRow" brand)
29 Schoolhouse Road
Somerset, NJ 08873
(800) 526-3921
www.oticonusa.com
Sennheiser Electronic Corp. (M)
1 Enterprise Drive
Old Lyme, CT 06371
(877) 736-6434
https://en-us.sennheiser.com/
Tour-Mate Systems (M)
1290 Blossom Drive Suite D
Victor, NY 14564
(800)-216-0029
www.tourmate.com
Williams Sound (M)
10321 West 70th Street
Eden Prairie,MN 55344-3459
(800) 328-6190
info@williamsav.com
www.williamsav.com
FM Systems Only
Comtek (M)
357 West 2700 South
Salt Lake City, UT 84115
(800) 496-3463
sales@comtek.com
www.comtek.com
EXMAX (M)
China
You can contact this manufacturer directly via email at sales@iexmax.com; however, Exmax products are typically sold through Amazon via listings like this one.
www.exmaxpro.com
Induction Loop Systems Only
AssistiveAudio (S)
2627 Algonquin Parkway
Toledo, OH 43606
(800) 224-9295 Voice
(419) 292-2169 Fax
www.assistiveaudio.com
Oval Window Audio (M)
33 Wildflower Court
Nederland, CO 80466
(303) 447-3607 Voice/TTY
www.ovalwindowaudio.com
Telex (M)
9600 Aldrich Avenue, South
Minneapolis,MN
(800) 392-3497
(612) 884-0043 Fax
www.telex.com
Infrared Systems Only
ALDs, Inc. (M)
#2-11220 Voyageur Way
Richmond, B.C., Canada V6X 3E1
(604) 244-0269
(800) 665-2537
(604) 270-6308 Fax
www.alds.com
Audex (M)
710 Standard Street
Longview, TX 75604
(903) 295-8244
(800) 237-0716
(800) 283-3974 Fax
www.audex.com
Lightspeed Technologies (M)
15812 SW Upper Boones Ferry Road
Lake Oswego,OR 97035
(503) 684-5538
(503) 684-3197 Fax
www.lightspeed-tek.com
QSC, LLC
www.qsc.com
Connect with QSC
Solutions for Hearing and Visually Impaired
Siemens Hearing Instruments (M)
P.O. Box 1397
10 Constitution Avenue
Piscataway, NJ 08855
(732) 562-6600
(732) 562-6696 Fax
www.siemens-hearing.com
Wi-Fi Systems for iPhone, iPad, and Mac Only
Arts Access International's "Accesslyve" System
Contact through web site only
www.artsaccessintl.com
LiveVoice 
May '24
Smartphone, Tablet, or Computer
User brings own device (typically a Smartphone)
LiveVoice.io/en
