Manufactured by Western Electric beginning in 1928. Originally used as a full range speaker system utilizing the 555W compression driver covering 100hz-5500hz. Later, the 597A tweeter and Western Electric TA4151 13.5″ woofers were added to make the “Widerange” system. This covered roughly 60hz to 12khz+/-. The 15A is 14′ long and has a mouth of roughly 56″ x 57″. The cut off frequency is 57hz. Sensitivity is 111db and efficiency is around 25%. The first film to use th W.E. 15A or the concurrent horns 12A and 13A was Don Juan starring John Barrymore.