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A small loudspeaker with the bass sound of a speaker three times its size has
been developed by a British company. The secret is simple: the speaker cabinet
is filled with bags of activated carbon. A loudspeaker cone is like a piston,
pumping in and out. Larger loudspeakers have a stronger bass because the air
inside a large cabinet damps this piston less than the small volume of air in a
compact cabinet. Now a company called KEF has found that putting bags of
activated carbon in the back of a small cabinet makes it sound three times
bigger. It claims the porous surface of the carbon fills with air as the speaker
cone moves back and releases it when the cone pumps forward, reducing the
damping effect.