"Improvements in or relating to Public Address Systems and like Sound Amplifying Arrangements"

Patent von Henry Joseph Round, 1934

S stage
M1, M2 microphone units
A1, A2 amplifiers
LS1, LS2 loudspeakers
PU1, PU2 pick-up areas

"It will be appreciated that with this arrangement the sound picked up upon either of the microphones and retransmitted in amplified form from its associated bank of loudspeakers, will be sound derived mainly from its own side of the stage, and accordingly the result achieved will be very largely to preserve the illusion that there is no public address system at all." [GB 435930]

 Abb. 1 aus [GB 435930]