Some years ago now, two men walked into a pub. They sat down to have lunch and an important business conversation, but were prevented from doing so by ear-splitting techno bursting suddenly from the speakers at full volume.
As they were the only two customers in the pub, they asked for the music to be turned down. The barstaff refused, so they asked to see the manager. The manager came across to the table where the two now thoroughly disgruntled customers were sitting and said, in a tone of voice usually employed when speaking to children: "We can't turn the music down. Let me explain what we're trying to do here. We're trying to build what we call a brand."
What the poor bar manager didn't realise was that his two customers were Tim Mason, then marketing director of Tesco, and Paul Weinberger, executive creative director of Tesco's ad agency, and the man who dreamt up the slogan 'Every Little Helps' one morning in his bathroom. The two men responsible for turning a third-rate 'pile 'em high, sell 'em cheap' supermarket into the most powerful retailing force in Britain proceeded to explain a few things about building brands, before leaving a pub which no longer exists.
Julian Treasure laughs hard when I tell him the story, told to me by Weinberger when we worked together. He's just told me one that's almost identical, only in his version the hapless pub staff weren't trying to build a brand; they were trying to "create atmosphere".
It's not surprising that pubs try to create atmosphere. Studies by companies such as Mintel show time and again that 'atmosphere' is the main criterion on which people choose pubs - way more than the range of drinks or the food offer. And yet atmosphere is difficult to define or pin down; it's something we feel, a combination of all the senses. Some licensees have an intuitive feel for it, and host pubs that have great atmosphere seemingly without trying.
Others simply seem unaware of what it is and make no effort to build it. And then there are those in between, people who recognise the need to create atmosphere and invest in doing so - with mixed results.
In a near-empty pub, a little music creates a hubbub that makes people feel more comfortable and relaxed. Sound is a vital component of creating atmosphere - but as the example above shows, many of us don't understand the relationship between sound and the atmosphere it creates.
"Many people think that 'atmosphere' is the same as 'noise', and they're not the same at all," says Treasure. "Although we're not conscious of it, we're surrounded by sound all the time. Most of it is accidental and unpleasant, and it affects us deeply.
"The world is getting noisier, and we get better at screening noise out, but it's really not good for us."
Treasure thinks about sound more than anyone else I've ever met, because he's chairman of a business called The Sound Agency, which advises clients such as M&S, Nokia, BAA and Intercontinental Hotels on how sound affects people and why brands should think more carefully about the sound they create. He's particularly passionate about noise in public areas and retail spaces, including pubs.
Sound affects us in four ways:
• Physiologically - a fire alarm will cause your body to release cortisol, the stress hormone, while the noise of waves can lower your blood pressure.
• Psychologically - music affects our emotional state profoundly, but natural sounds do too.
• Cognitively - we only have a small bandwith for processing what we're hearing, and if there are too many competing noises we become confused.
• Behaviourally - we move away from unpleasant noises (for example, drilling) towards pleasant ones, and if we're unable to do so it's bad for our health.
All these effects are highly relevant to the pub. Studies in shops show that inappropriate music makes people leave quicker and can reduce sales by almost a third.
"Architects and interior designers really focus on how a building looks, but don't often think about how it sounds," says Treasure. "But pubs, traditionally, had it better than most. Saloon bars and lounges had carpets and soft furnishing to deaden sound and create a level of noise at a low murmur, "enough to create privacy so that someone across the pub couldn't eavesdrop on your conversation, but not so much that you have to shout".
And then in the public bar area there might be hard floors, hard chairs and a jukebox, creating a louder level of noise for a more upbeat vibe.
"Music is problematic, because one person's choice is foisted on everyone else - whether it's a jukebox or piped music controlled by staff. But if you don't like it, if you have the option of moving to the other bar that's not a problem," says Treasure.
The problem arises when that choice - of moving away from noise you find unpleasant - is taken away. When the bars are knocked through into one big room, and that room is decorated with bare floorboards, big tables and charmingly mis-matched hard chairs, the noise level throughout the entire pub shoots up.
"When there's variety it's fine. What's sad to see in pubs now is a standardisation of noise at a level that can reach 90 to 100 decibels, with the sound booming around and people having no alternative but to shout," says Treasure.
Sometimes a noisy pub is what you want - in venues where young people are out on the pull, the inability to have a conversation reduces the need to think up witty and interesting comments and also forces you to lean in close to the object of your desire, promoting bodily contact.
But because we are adept at screening out noise, pub operators can make the mistake of thinking that we actually want noisy environments all of the time. "Television has killed conversation in pubs, and not just when the sound is turned up," says Treasure.
"If you're in a pub where Sky News is on with the sound turned down and you've got piped music over it, and you're trying to listen to the person sitting in front of you, it's worse than being irritating, it's actually unhealthy.
"We get what's known as schizophonia - your brain can't process all this competing information and it makes us irritable, tired and stressed." In other words, the exact opposite of what we came to the pub to feel like.
This is not a party political broadcast on behalf of the miserable 'no TVs or music in our pubs' fraternity. While it's wrong to think that noise equals atmosphere, the right sound mix clearly plays a part in creating essential buzz.
But what Treasure reveals is that getting the noise in your pub wrong can drive customers away. When failing pubs stick in more fruit machines, video games, loud music and TVs to lure people in, they often do the opposite.
Good licensees put a huge amount of effort into making sure their pubs look right.
But the way they sound - in terms of music, TV and background noise - is just as important. And as soon as you're aware of that, like an irritating pop hit, it won't leave your brain.