BBC LS3/7 Outside Broadcast Loudspeaker, 1973.

The early LS3/ 1 design, which was a large box with 15inch Goodmans paper bass driver crossed over to a Rola Celestion tweeter, was replaced by the LS3/7 design, built and developed by the BBC in-house. This speaker was a departure for the BBC as it was their first electronic crossover design. The active LS3/7 design incorporates a 12 inch bextrene driver crossed over to a soft-dome tweeter and represents a design philosophy based on two-way speakers due entirely to improvements in tweeter technology which rendered mid range drivers unnecessary.