BBC LSU/10 studio monitoring loudspeaker, 1948-1955. Uses Parmeko LS dome tweeter (later replaced by Lorentz units to improve high frequency response). Has built-in BBC LSM/8 valve amplifier (made either by Leak or SoundSales). Cabinet was made to BBC specifications by Lockwood of Harrow (originally a coffin manufacturer).

The first LSU/10 speakers were introduced in 1948. With an enormous 280 liter thick-wall cabinet, they had a workable frequency range from 40Hz to only about 6kHz. The 6kHz upper limit was adequate for in-studio monitoring in the BBC during the AM era (medium wave) from recorded music played out from 78 rpm shellac gramophone records with their own restricted frequency response.