Electromechanical musical instrument
An electromechanical musical instrument uses mechanical components to generate electrical signals , which are then electronically processed, amplified and made audible as tones via loudspeakers . During sound generation , the initially mechanical energy of the rotating or vibrating component, which alone would not be able to generate any significant sound, is converted into electrical energy. With regard to the sequence in which the sound is generated, one could speak of mechano-electric musical instruments instead of electromechanical instruments; but this designation is not common.
Examples are the electric guitar , the Hammond organ and the telharmonium . The body and strings of the electric guitar vibrate ; In the Hammond organ, an electric motor drives a rotating mechanism. In both cases, electromagnetic pickups act as sensors for the vibrations and convert them into sound signals .
history
An early electromechanical musical instrument was the telharmonium (also called dynamophone ). The American Thaddeus Cahill received the patent for this invention in 1897. As with the later Hammond organ, iron cogwheels (tone wheels) rotated in front of a coil with a permanent magnetic core in the telharmonium and generated electric current in the coil by induction , which made sine tones audible revealed. The instrument weighed up to 200 tons. Only three copies were built.
In the electromagnetic pickups of electric guitars and Hammond organs, electricity is also generated by induction. The pickup for the electric guitar was developed in 1931. In 1934 Laurens Hammond received a patent for his organ. The following year the Hammond organ was presented to the public.
principle
Mechanical component
In the Hammond organ, tone wheels, which resemble cogwheels, rotate, driven by an electric motor.
In electromechanical instruments without an electric motor, the mechanical component moves in an oscillating manner:
- String , plucked with the finger or pick (electric guitar)
- Sound plate or tongue , struck with a mechanism similar to the piano ( Fender Rhodes )
- Tongue, torn with a mechanism similar to the harpsichord (claviset from " Weltmeister ")
If the movement is to be picked up inductively, the rotating or oscillating component must be ferromagnetic .
Pickup
The mechanical movement is converted into alternating current:
- inductive : The rotating or oscillating medium changes the magnetic field of an electrical generator
- capacitive : The swinging medium corresponds to a capacitor electrode, the portion of an electrical resonant circuit is
- piezoelectric : The vibrating medium is mechanically fixed on it
Instrument types
- Electromechanical organs: Hammond organ
- Electric piano
- Electric guitar