12 String Electric Guitar Instruments
12 String Electric Fast Facts
The history and development of the electric guitar, like that of the steel-string acoustic, began in America. The feature that unifies all electric guitars is the pick-up. It is the pick-up that converts the sound of the instrument or the vibration of the stings into an electrical signal. This signal is then fed to an amplifier and converted back into sound by a loudspeaker. Key names in the evolution of the modern solid-body electric guitar are Lloyd Loar, Adolph Rickenbacker, Leo Fender and Les Paul. Much of the experimental work was centered around the Fender and Gibson companies – still among the market leaders today. Because the strong, five-piece neck construction Ovation employs, the necks on its 12 string guitars are built to the same, easy to play dimensions as those on its 6 strings.
A Brief History of the 12 String Electric Guitar
“Transducer” is the name given to any electronic or electro-magnetic device used to convert forms of physical energy into electrical energy. All guitar pick-ups are traducers of one kind or another. They convert the energy produced by the vibrating guitar strings into AC (alternating current) electrical pulses which are fed to an amplifier. The amp magnifies these pulses many times before the loudspeaker transforms them back into sound waves. 12-String electric guitars are generally fitted with magnetic pick-ups, although acoustic guitars are often amplified by means of a so-called contact transducer. Since magnetic pick-ups only function if they are close to the guitar strings, they are mounted on the body directly beneath the strings. Electric guitars may have one, two or three pick-ups. This means that, by means of the selector switch or volume controls, an individual pick-up or a combination of pick-ups can be used to get different sounds. The rhythm pick-up (which is nearer the center of the strings) has a more mellow sound than the cutting treble of the lead pick-up (which is close to the bridge).
How the single-coil Pick-up works
The simplest from of magnetic pick-up consists of a permanent bar magnet
with a continuous length of insulated copper wire wrapped around it several
thousand times. This winding is an electrical coil. The wire is extremely
fine – about the same thickness as one single strand of human hair.
The magnet generates a magnetic field around itself, and the pick-up is mounted on the guitar body so that the guitar strings actually pass through the magnetic field – and, because the strings are made of steel, they interact with the magnetic field. While the strings are at rest, the filed maintains a regular shape and nothing happens in the coil. But, as soon as a string is struck, its movement alters the shape of the field.
Some of the “lines of force” which make up the magnetic
field intersect the coil and, when the vibrating string causes the lines
of force to move, small pulses of electrical energy are generated in the
coil itself. If the coil is connected to an amplifier, these pulses will
travel to the amp in the form of AC.
The precise pattern in which the string vibrates depends on the
construction of the guitar and the way the note is sounded. Let’s say
the pattern is a figure-eight as shown below. If the string is an open
A tuned to concert pitch, it will vibrate at 440 cycles per second. In
other words, it will complete the figure-eight 440 times every second.
This means that the magnetic filed surrounding the pick-up will also by “altered” 440 times. As the volume of the note dies away, the distance between the pints +1, -1 and 0 become shorter until the string is at rest again. Nevertheless, throughout the duration of the note, the actual number of cycles per second remains the same. This tells the amplifier the pitch of the note – whether it is an A or a B, for example.
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