The Digital Signage Insider

A Sound Approach to Digital Signage Audio

Published on: 2009-04-29

If there was ever a subject to inspire debate among digital signage experts, sound would be it. Sure, people can go on about the best way to hang a screen, the best content production methods, and the best monetization schemes. But when it comes to sound, a lot of folks have a knee-jerk reaction either for or against it. At the crux of the issue is the undeniable fact that sound -- whether ambient, music, noise, voice or silence -- can have significant physiological and psychological effects on all of us. Consequently, a lot of people feel they should be able to take advantage of this to make their digital signs into powerful, attention-grabbing fixtures. Unfortunately, what many fail to consider is that unless you're a real expert at using sound, you're probably going to do it wrong.

Why you shouldn't use sound

When people ask me about using sound in their digital signage content, I always start my pitch this way: don't. It's a lot easier to reduce your sign's effectiveness with bad sound than it is to improve it with good sound. What's worse, improper use of sound does more than simply ruin your digital signage content: it poisons the entire area it permeates, creating a place that people want to get away from as quickly as possible. Annoying soundscapes have been shown to reduce shopper dwell time. In fact, some venues have actually used those noisome noises to their advantage. Case in point: a number of small businesses that have had problems with loitering teens are using a device called the Mosquito to emit a shrill 17.4 Khz sound that is only audible to most people until around age 23 or 24. While older folks (you know, like most people in their mid-20s) are unaffected, the young hear a horrible whine that keeps them away. Kind of like a doggie whistle for your kids. But I digress...

Even if you do create a sound palette that's pleasing to your audience, there are two other large potential pitfalls that must be avoided. First, if your digital signage audio competes with the sounds from your host venues, the venues may decide to disconnect you. Maybe they'll tell you about it. Maybe they won't. Or, maybe those in charge won't even realize it has happened, since big potential problem number two is that "employee fatigue" may encourage workers to disconnect or otherwise sabotage your digital signage equipment. Quite simply, hearing the same ten-minute sound loop over and over for eight hours could compel your otherwise nice checkout clerk to sever your speaker wires. Don't believe me? I've actually witnessed this happening in person. (It wasn't one of my networks, so I... ahem... didn't say anything at the time.)

Why you should use sound

By now, you're probably wondering why anybody would be crazy enough to include sound in their digital signage networks, seeing as the pitfalls look pretty awful. Well, thankfully the good folks at Arbitron have done the research (PDF format), as illustrated by these results from way back in 2005:

As the chart shows, more than 40% of the shoppers who heard a retail audio advertisement made an unplanned purchase. Specifically, 41% of shoppers who recall hearing retail audio ads made a purchase they were not planning on making after hearing a commercial or announcement about the product in the grocery store or drugstore.

Additionally, more than one-third of the shoppers who heard a retail audio advertisement purchased a different brand. We've all heard stories about what percentage of brand decisions are actually made in-store. While that debate is sure to carry on for some time, at the very least the Arbitron research confirms what seems like common sense: we're easily swayed at the first moment of truth, particularly if we don't have a strong brand or product loyalty to begin with.

Are there any best practices for using sound?

You bet! First of all, go out and buy a copy of Julian Treasure's Sound Business. Adrian Cotterill (of DailyDOOH fame) gave me a copy of this book a few years ago, and I still find myself turning to it when analyzing whether using sound is appropriate for a given client/venue or not. Treasure's chapter on sound practices for shops and other retail spaces outlines essential considerations for any space you might consider putting digital signs in, not necessarily just retail. Among the most important is to think about the varied (and many) background noises already present in the environment. While I'll defer to his expert observations for deciding whether to use sound at all, I can provide a few tips for determining if sound is being used correctly on a spot-by-spot basis. Here at HQ, we consider the following four points each time we run out a new piece of content that's going to use sound:
  • Don't rely on sound alone to make your message. If your message doesn't work visually, you're relying too heavily on your audio. Even in the best circumstances, your audio will likely be available to only a small portion of your sign's total audience.

  • Use audio to punctuate an already strong and compelling visual message. Your audio and video should be making the same points. Don't say one thing but show another.

  • Your visual messages should be comprehensible without sound. Even if you find that audio adds considerable impact to your message (and sometimes it really can), your visual messages should be completely understandable without any kind of sound.

  • Consider closed captioning ONLY if your visual storytelling is confusing. If you find that you're turning to closed captioning for spots with an audio track, your visuals aren't clear enough. You shouldn't need to closed caption a voice over to make your spot understandable.
Sound absolutely can make digital signage networks better. But there are many external variables that affect whether it does make them better, or whether it makes them worse. Frankly, our advice to clients who are on the fence is typically to not use sound -- at least not to start. It requires a lot of experimentation, very detailed record keeping, additional coordination with the venue owner and on-site staff, and additional ongoing monitoring to see if there's any benefit. For many of the folks we work with, that extra effort is better funneled elsewhere, whether it be into additional content production resources or different types of integration with the host venues. And of course, there are plenty of venues who simply say they won't allow sound. This makes the decision easy for the network owner, but also highlights just how divisive a bad sound experience can be.

Do you use sound on your digital signage network? Why or why not?


0 # Jeff Metzger 2009-04-29 16:07
A majority of the hundreds of installations that we perform daily throughout North America do not have sound. However, we are seeing growth in focused sound applications in retail as well as more installations in professional lobbies - vet, dental, health offices which require sound.
+1 # Christian Xell 2009-04-29 16:12
Sound? No way. We made the experience that the sales staff gets crazy. We do not see any advantage by the usage of sound. Our hardware is also not ready to play sound :-). But this was wanted when we developed our hardware.
-1 # Bill Gerba 2009-04-29 17:17
Jeff: Interesting, and I'd have to agree that smaller locations with less transient populations tend to be more likely to at least try sound. But the annoying loop at the dr's office is just as likely to put me (or an employee) in a bad mood as it is in a grocery store, don't you think? Christian: Yeah, as a number of people have told me, employee fatigue should have been the #1 reason against sound on my list :)
-2 # Pat Hellberg 2009-04-29 20:36
Couldn't agree more. It's an unfortunate reality that we still have to worry about the worst case scenario. But we do. If your content includes audio that is driving the on-site employees insane, the worst case scenario is they will find a way to sabotage the audio system. I've seen it happen also. Another good argument, as if we needed another one, against playing broadcast spots in store. Without music and/or narration, most broadcast spots make no sense. A TV spot, played without sound in-store, does more harm than good.
-1 # Stephen Ghigliotty 2009-04-30 12:25
I programmed and managed a 600 location network across Canada and the States a few years ago where every location was indeed audio enabled. Our sales folks were of the mind that the louder we ran the more likely we would sell ads. What was the result? Sales folks working in proximity to the screens in full uproar; complaining to management and even starting blogs about the situation. Bill's advice to move cautiously and thoughtfully with audio is sound. Read and learn...
-1 # Jason Goldberg 2009-04-30 15:42
Frankly due to the lower hardware costs and content development costs of audio, there are many retail merchandising challenges that can be solved quite effectively by a Sound Only solution where a video based solution wouldn't have a favorable ROI. As someone who has deployed over half a million listening stations to music retailers (back in the old days when there were physical music retailers), it's quite possible to do. People like Martin Lindstom in "BrandSense" have done a pretty thorough job of documenting that fact that multi-sensory branding can be exponentially more effective than focusing on any one sense. So if you're going to do audio (in retail), you do need to consider some factors: Employee Fatige - Employees exposed to repetitive and irritating audio are going to find a way to disable your display. (we use motion sensors and timers to limit audio when a customer isn't actively engaged with a display). Volume Levels - Ambient volume in the environment will change throughout the day and certainly from store to store, so you can't set a default volume at the factory, or even in the store during set-up. You need to use dynamic volumes that adjust to current ambient levels. Volume Control - If the audio has important information delivery (vs. being a UI element or attraction device) then you need some use volume control, but it needs to be non-persistent (so the volume resets for the next user/shopper). Think about sales assisted experiences. We always design our experiences to be multi-modal (self service customer, sales assisted customer, sales associate education). When a sales associate is helping a customer at the display, we give them the ability to easily "snooze" the audio for a specific period of time, so they don't have to talk over it. Directional Audio - There are a variety of technologies out there, that can work in the right environments, but they have trade offs. Parabolics can be expensive and aesthetically challenging to install. HSS panels can have audio bounce/leakage problems. None of the directional solutions support much dynamic range.
+1 # Julian Treasure 2009-05-01 17:52
Thanks for the namecheck Bill - I have tweeted your excellent and thoughtful blog in return. Good to see such well-considered comments also. It's reassuring that everyone sees the perils of uncontrolled intrusive AV in public spaces. I blogged a while ago about the screens in the Milan underground, which batter the poor travelers waiting for trains with sound offering nowhere to run, nowhere to hide. We will surely have to endure some unpleasant testing like this of the boundaries between adding value to retail experiences and irritating the heck out of people... but I believe the future will see a holistic approach to space design that takes into account all five senses from the start, designing to take advantage of what Prof Charles Spence calls 'super-additivity', where 1 1 1 1 1=20 or more.
-1 # Roi Iglesias 2009-05-04 10:58
Hi, Sound and music are a great team at POS. If you work sound and music thinking in consumers you have their atention. Music, sound and content, produced specifically for digital signage, get the channel to work, that the public is better informed, and that employees do not perceive noise. We are working some channels with music, sound and video, with Kentia Software. The video content is only sound when they are relevant, if not noise pollution. Music and sound affects the way shoppers (retail week)
+1 # Lyle Bunn 2009-05-04 21:25
Why leave sound/audio in the communicators toolchest as digital sigange is pulled out ! Suitable apply, as with touch, and even smell audio can augment the messaging, its influence and call to action, adding to brand recognition. Suitable and appropraite to the environment are the words I most read into your comments Bill (and other commentators). Interesting to note that "best of the best" content award winners almost always have audio. (Smirnoff, Gilette, etc.) Talking head - bad, Raw noise - bad, Long form spot spot (i.e. Movie Trailer - bad. Familiar tones and tunes in context - Audio good.!
+1 # Christian 2009-05-06 23:16
Bill, Glad you touch on this subject as well. "Don't rely on sound alone to make your message." and "Your visual messages should be comprehensible without sound..." very much hits home; especially from the network operator and agency perspectives. Currently, I know for fact that the lack of audio alone could be a "deal killer," and it is good to see the work is getting out that networks and content can work effectively without it, or with other solutions as well. Check out and if you have the time. I would love your thoughts and I'm sure Paul would love it as well. Great post! Gerba hits again. :)
-2 # Kelly Parks 2009-08-09 19:18
Hi Bill, Thanks for the great post. This is a major issue I deal with with our customers (mostly retail shops). We've moved away from standard audio and are now working with directional audio solutions. Audio still isn't right in many situations, but I've found that using this type of audio I can use it in more situations. The primary issue customers seemed to have was annoyance: they were worried about annoying the customers or their staff. Directional speakers gets around this by only delivering sound in the target and not outside. I saw that one of the other comments mentioned directional speakers and referred to the ultrasonic speakers. We tried these, but the customers complained about the sound quality. We are now using Sound Shower speakers from Panphonics, and are happy with the results. Do you know if any studies have looked at directional audio with digital signage. Such a study would help my pitch to customers, as I feel that our use of directional audio helps to make us stand out from other local installation companies. -Kelly P.
+1 # Bill Gerba 2009-08-10 20:13
Hi Kelly, I've not heard of any studies that look at such a specific topic... in fact, I've never seen a study that looked at the use of directional audio (vs "regular") at all, though I'd love to!

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