The holy grail of loudspeaker design has always been to generate big bass from small boxes. The trouble is, the laws of physics make this almost impossible to achieve, as bass extension relates directly to efficiency and cabinet size.

Continuing a 40-year tradition of genuine design innovation, KEF engineers have now developed a way of overcoming this apparently insoluble limitation. It's called Acoustic Compliance Enhancement (ACE), and it works like this. In conventional speakers, cone motion is restricted by the acoustic pressure in the enclosure as the air is alternately compressed and expanded by the cone moving in and out. The smaller the enclosure, the greater the pressure that acts on the cone. By dramatically reducing this pressure, ACE allows the cone to move as freely as it would in a much larger cabinet, generating bass extension out of all proportion to its actual size. This is achieved by introducing granules of activated carbon into the enclosure - a material containing millions of pores ranging in size from visible fissures to holes a few molecules across.
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