Thirty seconds is a short time in which to explain yourself, especially if you're only using music.
A composer working in advertising must communicate myriad emotions, while echoing visuals they haven't seen, to the satisfaction of clients they have never met, who know nothing about their trade.
Writing music for ads is a tricky business and, as such, not everyone with an ear for music is capable of doing the job. Composers who can rattle out film soundtracks or conduct big bands often prove hopeless when it comes to scoring a beer ad.
"Composing for commercials requires a different mind-set," Karen Elliot, an agent and music supervisor at Hot House Music, says. "Clients want you to get a lot of different emotions across. You've often only got 30 seconds and the brief may require you to do a lot in that time."
If a TV spot is to be successful, it is vital that its music matches its visuals and dialogue. To this end, some composers insist on seeing the rushes for a commercial before they score the music for it.
This is not always practical. Besides, there are many composers who would sooner be involved at the beginning of the creative process - after all, a composer that understands creatives and can help them articulate what they want is well-placed to deliver the right music for them.
Stuart Douglas, a director at the production company Nice Shirt Films, adds that composers who write well for advertising tend to be those who also truly comprehend the mechanics of the medium - and the jargon. "They need to understand when an agency talks in agency language," he says.
"They need to be able to interpret these marketing terms into musical references."
However, this level of understanding is not always reciprocated. "Composers also need to be very thick-skinned," Douglas points out. "They're dealing, on the whole, with non-musical people. Sometimes, the questions agencies put to composers really make me cringe."
Then there are client whims to deal with. It is quite common for a client to call a composer during a recording to suggest minor changes to the music, which can't help but ruffle the feathers of the more precious composer.
Those who thrive in this industry are those who can re-arrange their pieces quickly, without taking offence that their musically perfect score is not quite what the client wanted.
But despite the inevitable niggles, those suited to advertising soon become engrossed by its unique demands. There are many composers who specialise in ads, build close working relationships with creatives, directors and producers and are subsequently used again and again.
And the results? Whether it's the classic original scores such as the one Collett Dickenson Pearce commissioned for Benson & Hedges' "iguana", or creative interpretations of classic pieces, such as the soundtrack to Lowe's "ice-skating priests" for Stella Artois, there is plenty of proof that music has a greater role to play in advertising then merely instructing us to do the Shake 'N' Vac.
Campaign asked the UK's top advertising and production companies to name the composers they rate the highest. Below, we list the top five.
THE FIVE FINEST COMPOSERS IN ADLAND, ACCORDING TO A CAMPAIGN POLL
Paul Hart - Joe & Co
Hart is a prolific composer who toured as a pianist and violinist with the jazz duo Cleo Laine and John Dankworth before teaming up with his long-term composing partner, Joe Campbell, to launch Joe & Co in 1977.
Since then, Hart and Campbell have written music for performance and television, as well as for advertisers such as Kellogg, Reebok, Land Rover and Hamlet. They also composed the music for Carling Black Label's famous "dambusters" execution.
Throughout his career, Hart has picked up awards for Samsonite, Holsten Pils, five, John Smith's and Hofmeister.
"He's very intuitive," Glenn Holberton, a producer at Loose Moose, says.
"He understands what you want and his musical skills and his ear are second to none."
Peter Raeburn - Soundtree Music
Raeburn's advertising expertise lies not only in his ability to compose appropriate scores, but also in his ability to source music.
"What is great about Peter is that if you sit and have a chat with him, somehow or another, he gets inside your head and knows what you're after," Walter Campbell, a creative partner at Campbell Doyle Dye, says.
In 1999, Raeburn suggested that Campbell and his then creative partner, Tom Carty, use a little-known track by Leftfield as the soundtrack to their Guinness "surfer" spot. The rest is history.
Raeburn's company, Soundtree Music, has been running since 1997. During that time, Raeburn has scored numerous commercials including Guinness' "dream club" (again with Campbell and Carty) and Levi's "twist". However, his talents are not limited to advertising - his film credits include Jonathan Glazer's feature Sexy Beast.
John Altman - Jeff Wayne Music
An accomplished player of the soprano saxophone, Altman has played with the likes of Muddy Waters, John Lennon, Jimi Hendrix and Eric Clapton.
He worked as a musical director for Van Morrison during the late 70s and arranged, conducted and whistled Eric Idle's Monty Python anthem, Always Look on the Bright Side of Life.
Altman's film credits include Titanic and Shall We Dance? and his score for RKO 281: The Making of Citizen Kane won him an Emmy.
On top of all of this, Altman has written and arranged music for ads including Levi's "Odyssey" and Renault "Thierry and Animal".
McCann Erickson's executive head of TV, Frank Lieberman, says: "John is incredibly knowledgeable when it comes to music, particularly big-band music. If I wanted to have something orchestral or jazz-oriented, John is who I would want to talk to because he understands that whole genre."
Peter Lawlor - Water Music
Lawlor's production company, Water Music, has been running for 15 years, during which time he has worked for advertisers such as the RAF, Vauxhall, Rowntree and Ford.
One of his most celebrated scores was a piece entitled Ice, which expertly supported the 2002 Orange commercial "night night X". He also composed the rock soundtrack to Levi's "creek", a score that Lawlor got to number one under the guise of a band called Stiltskin.
Whenever possible, Lawlor chooses to wait until an ad has been shot before he scores it.
Tessa Lawlor, a producer at Water Music, adds: "Peter's principle is that every piece of music he composes for an ad should have three hooks in it. This is what a record would have, only he does it in 30 seconds, as opposed to three minutes."
Anne Dudley - Hot House Music
Dudley is known primarily as a film composer, having worked on movies such as The Crying Game and Buster.
"Advertisers come to Anne for this reason," Karen Elliot, an agent and music supervisor at Hot House Music, says. "They know they're going to get a very filmic sound. Her strings and orchestral arrangements are very distinctive, very full, lush and melodic."
Dudley's ad credits include "Devil's Island" for Stella Artois and Reebok's "field of dreams".
During her career, Dudley has forged a close working relationship with the director Tony Kaye and has collaborated with him on numerous commercials, as well as scoring his feature film American History X. She has also worked with Pulp, Elton John and Rod Stewart.