The Electro-Theremin, often called the Tannerin, is an electronic musical instrument developed by trombonist Paul Tanner and amateur inventor Bob Whitsell in the late 1950s to produce a sound to mimic that of the theremin.[1][2] The instrument features a tone and portamento similar to that of the theremin (or thereminvox), but with a different control mechanism. It consisted of a sine wave generator with a knob that controlled the pitch, placed inside a wooden box. The pitch knob was attached to a slider on the outside of the box with some string. The player would move the slider, thus turning the knob to the desired frequency, with the help of markings drawn on the box. The Tannerin doesn't actually sound much like the theremins of the time.
The instrument was custom-built at Tanner's request. Tanner appreciated the theremin's sound, but wanted greater control of pitch and attack. The Electro-Theremin uses mechanical controls, a long slide bar for the pitch (analogous to the slide of the trombone that was Tanner's main instrument) and a knob to adjust volume. This contrasts with the hand movements in space that was the original theremin's signal feature. The Electro-Theremin also produces a slightly less complex timbre than the original. This is not due to the nature of the instrument, but due to Dr. Theremin's intentional harmonic generation in the output of the Theremin, which Tanner did not do.
Tanner played it for the 1958 LP Music for Heavenly Bodies, the first full length album featuring the instrument,[3] and played it subsequently on several television and movie soundtracks—most notably on George Greeley's theme for the 1960s TV series My Favorite Martian—and on an LP entitled Music from Outer Space. Most famously, Tanner played his Electro-Theremin on three tracks by The Beach Boys: "I Just Wasn't Made for These Times", "Good Vibrations", and "Wild Honey".
Tanner's prototype Electro-Theremin appears to have been the only one made. Tanner sold the instrument in the 1960s because he believed that newer synthesizers made it obsolete.