The electric guitar-on-a-slab-of-wood found in today’s rock band has a vibratory tone generator. This involves the translation of mechanical or acoustical vibration into an electrical signal that can be processed by electrical circuitry and turned into sound by a loudspeaker. Keyboards in use today that have a vibratory tone generator include the Wurlitzer and Rhodes electric pianos and the Hohner Clavinet.
The roots of these instruments can be traced to 1884, when the German Ernst Lorenz built an instrument using the principle of self-maintained vibration typical of electric door buzzers. Upcoming columns will explore this history.
We call the device that translates mechanical energy into an electrical signal a pickup. There are two basic kinds of pickups: contact and proximity. A contact pickup is directly attached to a vibrating element, for instance the sounding board of an acoustic piano (the FRAP pickup is of this type). A proximity pickup (e.g. the Helpinstill) is placed near the vibrating element, but doesn’t touch it. This is typical of most electric guitars and the Wurlitzer and Rhodes electric pianos.
The contact pickup grew out of radio microphone technology. Oskar Vierling, the preeminent European designer of early vibratory instruments, pointed out:
After the amplifier and microphone were developed so that the sound of instruments could be satisfactorily produced, the thought was immediately obvious to provide musical instruments with such arrangements. F. C. Hammond was the first to put this idea into practice [about 1921] and thus establish a new direction in the development of the electrical musical instrument.
In 1926 Fred Roehm and Frank Adsit developed the Radiano, a contact pickup for the piano, and touted its advantages over use of the ordinary microphone in the radio studio:
Reproduction of piano tones has been one of the major problems confronted by broadcast engineers. No matter how fine the adjustments, even with a specially built piano, it has not been possible always to eliminate the excessive vibrations, sometimes resulting in a tinny sound. These difficulties are entirely eliminated by the Radiano. There is no metallic sound, no microphone roar, and all tones and overtones which hitherto have escaped fidelity of reproduction are distinctly audible. Demonstrations are said to have shown it capable of tremendous volume without distortion.
It is probable that most of the early contact pickups were more an attempt to extend broadcast fidelity than to create new instruments.
Roehm had outlined some of the economic reasons for the development of the Radiano:
Our device is eagerly sought by the piano manufacturers because the basic patents on the self-players are about to expire and soon will be adopted by anyone who cares to use them. The industry has been searching vainly for something new to stimulate piano sales and to counteract the increasingly severe inroads being made by radio and the improved talking machine types [phonographs].
But the contact pickup didn’t create a fundamentally new instrument capable of revitalizing the slumping piano industry. It is ironic that as these pickups were improved, they more faithfully reproduced the actual sound of the instrument to which they were attached, instead of creating new instruments.
Clearly, designers would have to turn elsewhere for a new instrument. Proximity pickups were soon developed which held more promise for the beleaguered piano industry. Proximity pickups were of two basic types, electrostatic and electromagnetic. In this month’s column we’ll focus on the electromagnetic type. This type of pickup features a permanent magnet or an electromagnet placed close to a stretched steel string (as in a guitar or piano). A coil with a soft iron pole is also mounted near the string. When the string vibrates at a certain frequency (pitch), it induces a voltage of corresponding frequency across the coil. This signal can be translated into a sound with the same pitch.
Much of the development of the electric piano with electromagnetic pickups was carried out in Germany. In 1931, Hiller constructed the Radiopiano, using a series of electromagnets placed over the strings of an acoustic piano. The first demonstration took place at the Norag Broadcast station in Hamburg. Little is known of the instrument’s subsequent history.
At about the same time, the Bechstein piano company introduced the Neo-Bechstein, an electromagnetic piano designed by Oskar Vierling and Walter Nernst, a Nobel Prize winner in physics. Typical of electric pianos of the era, the Neo-Bechstein had no soundboard. A soundboard simply isn’t necessary unless one wishes to radiate airborne sounds from the strings. The strings of the Neo-Bechstein were divided into groups of five and a small electromagnet was provided for each group.
Since there was no soundboard to cause dissipation of energy, the strings were required to vibrate only slightly. They could therefore be shorter, lighter, and under less tension than in the normal piano. Double strings were used only in part of the middle register, and triple ones not at all. All of this implies a lighter framework and a lighter hammer, which in turn implies some potential problems for the performer. Fortunately, Nernst resolved the problem by providing hammers of the usual weight to be struck by the performer. These heavy hammers struck not the strings but a nearby rail; the impact drove a “micro hammer,” perhaps one-twentieth the weight of a normal one, up to hit the string itself.
This design caused some interesting musical possibilities. One reviewer noted that “…the tone is purer [fewer high partials] owing to the reduced amplitude of the vibrations. And since the strings lost very little energy due to the absence of the soundboard, their damping was greatly reduced. Bass strings could sustain for up to sixty seconds. This in conjunction with the use of a volume pedal opened new organ-like possibilities.”
The design of the Neo-Bechstein made it similar in some ways to the clavichord of Bach’s time. Vierling explained the parallel:
In instruments with little vibration, the damping is relatively small, since the reflection plays an insignificant part. The tangent piano [clavichord] was therefore already equipped with special dampers which could be applied to the strings by means of a stop pull, the so-called “lute stop.” These dampers had the effect, in addition to reducing the duration of the echo sounds, of pleasantly influencing the timbre. Nernst also had built this contrivance into his grand piano Neo-Bechstein . This becomes even more effective through the electric amplification.
In a curious note, the Neo-Bechstein speaker cabinet incorporated an “electrical gramophone” [phonograph] and a “wireless receiver” [radio]. This was a typical arrangement on electric pianos well into the Forties. Perhaps the piano industry concluded, “If you can’t beat ’em, join ’em!” Next time, more on the early electric piano.
JANUARY 1978
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