User Manual

NORD ELECTRO 2 V2.2x 9. History: The story behind the Electro 2 instruments
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Laurens Hammond retired at age 65 in 1960 and passed away in 1973. One year after his death, the factory
stopped making tone wheel organs. From then on, the only organs that were produced had electric circuits
-- but that's another story.
T
HE LESLIE SPEAKER
The rotating speaker effect in the Nord Electro 2 is a digital em-
ulation of the Leslie 122 speaker cabinet. Leslie cabinets are
stand-alone devices. Their preliminary design was to amplify
and add modulation effects -- i.e., chorus and tremolo -- to the
sound generated by an electric organ such as those made by the
Hammond Organ Company.
What's the story behind this famous accessory to the Hammond
organ? It goes back to 1937, when musician and inventor Don
Leslie bought a Hammond Model A. Don was interested in
finding a musical instrument that could sound like a pipe organ,
and he decided to buy the Hammond because he figured it
sounded close enough. To save money, he chose not to invest in
an accompanying Hammond tone cabinet because he thought
he could make his own speaker system.
However, he wasn't satisfied with the organ sound coming from
his first fixed-speaker design because the sound was too static.
He wanted to create some kind of motion in the organ sound,
much like the way the sound of a pipe organ moves around a big
church because the pipes themselves are spread out across many
large ranks - collections of pipes - that cover the frequency range
across an organ console's keyboard manuals and pedal board.
For several years, Don experimented with various combinations
of speaker configurations and rotating components, and in 1940
he completed his first version of the rotating-speaker concept.
Here is a picture of the inside of the Hammond tone wheel box. It's the basic design that
elevated Hammond to the top of the organ manufacturer mountain. Each note on the Ham-
mond corresponds to a tone wheel. Every tone wheel has it own pick-up comprising a mag-
net with a coil. The pitch of the sine wave generated by a tone wheel is determined by the
number of notches on the edge of the wheel and the wheel's rotation speed. Every time a
notch in the wheel passes the magnetic field, it induces a voltage in the coil. The more
notches and the faster they pass, the higher the pitch.
Leslie 122 rotating-speaker cabinet.
A close-up view of the nice woodwork on a Leslie
122 speaker cabinet.