A Balanced Armature, cone loudspeaker
Cabinet Dimensions mm; W=362, H=356, D=171
See the KB 232 Speaker in the Radio Museum
In the centre photo above it will be seen the original Balanced
Armature speaker has been replaced with a "Silver Ghost" permanent magnet
moving coil speaker driver, which is a probably from 1933.
Ghost speech coil resistance 9 ohms.