Air loudspeakers could make light work for roadies

It may be the end of the road for the roadie. The Sherpas of rock, who can't pass a microphone without counting up to two, could soon find the vast speakers they heave for a living replaced by inflatable ones. These will weigh next to nothing and could be packed into a bag by the average groupie.

It may be the end of the road for the roadie. The Sherpas of rock, who can't pass a microphone without counting up to two, could soon find the vast speakers they heave for a living replaced by inflatable ones. These will weigh next to nothing and could be packed into a bag by the average groupie.

The first of the new generation of speakers will be on sale in WH Smith and the Gadget Shop at Christmas, costing about £30. Made by Ellula Sounds, from Loughborough in Leicestershire, the system uses British technology – previously used for flat speakers – to produce the first inflatable sound system.

Soundtube, a company from the United States, is also working on an inflatable design, using its own technology.

Both could make redundant the rock-tour roadie's task of shifting and setting up huge speakers for concerts. Some famous names have broken into the rock world through such work: Lemmy, lead singer and bassist with Motorhead, worked as a roadie for Jimi Hendrix.

Roadies' strength is essential because normal speakers, which rely on old technologies, need solid wooden boxes. The driver uses a magnet and wire coil to convert the electrical signals from an amplifier into energy, which moves the paper speaker cone back and forth. But the only way to make them louder is to get them to move larger amounts of air, which entails having both a large speaker cone and a large rigid enclosure for the air.

With conventional cones, the enclosure must be rigid to make the air move uniformly. A soft edge would mean that the power of the moving cone would simply be dissipated by the flexing of the walls.

However, the technologies being used by Ellula do not need a rigid enclosure. The company, set up by Joe Stephens, a recent graduate of Loughborough University, relies on flat-speaker technology developed by NXT, a British company. It uses "soundboards", which can be any shape at all and have already been used for flat speakers.

Ellula is talking to Budweiser about making giant inflatable Budweiser speakers shaped like beer cans.

Soundtube, an American company based in Park City, Utah, is also developing inflatable systems, although more like the standard speaker form. These would have a large rigid board with a speaker cone, and an inflatable "enclosure" which would be pumped up to a high pressure that would make it rigid. The result: instant speaker, once you add an air hose.