Le Caine built the Electronic Sackbut between
1945 and 1948. It is now recognized to have been
the first voltage-controlled synthesizer.

Hugh Le Caine at the Sackbut.

In 1945, when the first Sackbut was built inside a desk, Le Caine visualized an instrument in which the operator would control three aspects of sound through operations on the keyboard in three co-ordinates of space: vertical pressure was to correspond to volume; lateral pressure to pitch change; and pressure away from the performer to timbre.

The control devices were force sensitive. They would alter the sound in response to changes in pressure, something the operator could feel without carefully watching the controls. The timbre controls, however, were soon considerably expanded and could no longer be operated by a single device.

Two innovative techniques stand out in the design of the Sackbut: the use of adjustable wave forms as timbres and the development of voltage control. It is in this regard that the Sackbut is recognized to be the forerunner of the synthesizers of the 1970's.

Below:

• The 1948 Prototype
• Playing the Sackbut
• The Sackbut Synthesizer
• Inside the 1971 Sackbut

The original 1948 Sackbut. The prototype of the Electronic Sackbut, completed in 1948, is now in the collection of the National Museum of Science and Technology. As seen here, it was built on a minimal stand using three legs and three cross pieces. Le Caine did not feel it was an appropriate use of his time to improve the appearance of the instrument by removing the staples and scraps of cloth from the boards that made up the stand. This photograph was taken in 1954 soon after Le Caine began to work full time designing electronic music instruments at the National Research Council.

The right hand controls the keyboard, playing one note at a time, and applying both vertical pressure to affect volume and horizontal pressure to affect gradual change in pitch. The left hand controls several aspects of the timbre of the sound.

The control of timbre on the Sackbut was accomplished by the left hand, each finger operating a separate pressure-sensitive control.

The device to continuously alter the wave form was operated by the index finger of the left hand. A moveable pad, shown by dotted lines, made connections at any point within the larger grid of possibilities.

In 1969, Le Caine began to
redesign

The commercial prototype of the Sackbut Synthesizer.

the 1948 Sackbut
using modern techniques.
By 1971 this working prototype was completed, and there was an attempt to manufacture the instrument commercially as a voltage-controlled electronic keyboard instrument.

The final Sackbut used integrated circuits for the level controls and had an extra octave position, bringing the range of the instrument to seven octaves, its envelope control could be played in reverse without extra adjustments. Plans were made for an instrument with three oscillators but this was never built.

Le Caine also designed pressure sensitive devices to control aspects of timbre (to control the degree of frequency modulation with low register noise, and the addition of high register formant frequencies). There was also a device for continually and quickly adjusting the wave shape.