In 1982, Celestion broke new ground in loudspeaker technology when they presented the SL6, a compact hi-fi speaker featuring the first ever metal dome tweeter, made of copper and designed with the help of laser interferometry.
They followed this model up with the SL600, which used rigid honeycomb alloy called Aerolam instead of wood in the speaker casing; a material previously used only in the aerospace industry.
Around that same era, another version of the copper-domed model, with both the Aerolam cabinet and improved crossover elements, was marketed as the SL600si, also with dual inputs.Grace's Guide is the leading source of historical information on industry and manufacturing in Britain.This web publication contains 122,428 pages of information and 185,453 images on early companies, their products and the people who designed and built them.Since 1956, all Celestion chassis drivers have been stamped with a date code (two numbers and two letters), denoting exact date of manufacture.
The codes are added on the production line and are placed on the speaker's chassis leg, on the front gasket or on a label on the magnet edge.
The company grew rapidly, but was hit by the depression.