Sound~ Human beings are naturally sensitive to sound & meanings. Of course, this powerful association comes naturally right from the first sound we could hear our mother’s heartbeat. Sound evokes memories, experiences and lead to certain behaviors like these:
Experiments have shown that when music in restaurants is played slower than the rhthym of heart beats ~ we tend to eat slower.. Been to las vegas ~ the revenue from slot machines  dropped dramatically when the winkling and tinkling of the slot machines were removed.
Audi chose a combination of heart beat + Piano + breath as it’s audio branding initiative. Mercedes Benz got the precise and appealing sound for closing of a car door.  Victoria’s Secret uses a special classical music in it’s stores to support the premium image. Renault has a special ‘Hum’ of engine and the ‘Swish’ of windscreen wipers.
Of course Iphone users are familiar with the ‘crumbling’ sound when you trash data. The jingle of Intel Inside and Microsoft are pretty well known. Kellogs has the special crunching sound to indicate the crispiness of the snacks. 
Couldn’t resist compiling and putting together world class brands using audio branding 
Brands chosen : Starbucks, Audi, Bang & Olufsen, Renault, Toys R Us, Kellogs, Daimler Chrysler, Microsoft, Intel, Abercrombie & Fitch, Victoria’s Secret, Ford 
It’s the experience that matters!!!! &Successful brands are well aware of this fact. More on Sensory Brands : Visual Branding