DescriptionMoving-iron cone speaker 1929.png English: Early Paratone cone loudspeaker from advertisement in 1929 radio magazine. Loudspeakers that used...
published (or registered with the U.S. Copyright Office) before January 1, 1929. Public domain works must be out of copyright in both the United States and...
more efficiently. So horn loudspeakers produced far more sound power than cone loudspeakers from a given audio signal. The weak vacuum tube amplifiers in...
