Mager invented two different variants of the Sphärophon. The first version was similar to a
Theremin, but Mager's design had the capability to change the
timbre of the sound that was produced as well as utilize discrete
pitches. His second prototype was
keyboard-based but used a
radio frequency oscillator as well. This instrument was capable of producing
quarter tones of an
octave. In many of his instruments, including the Sphärophon, Mager experimented with the
drivers in the
loudspeakers to achieve different sounds as well. == Public demonstration ==