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The quality piano of the 20th and 21st centuries is a
technological masterpiece, a dynamic arrangment of over 200 strings and
9,000 parts overall (Steinway claims over 12,000 for its grand). Though
its concept may be relatively simple, its position as the ruler of
instruments is undisputed. Yet most people who play pianos have little
idea what is between the ends of the keys they play with their fingers,
and the sound they hear with their ears. Let's take a look at what
lurks inside your piano's dark inner chambers.
THE KEYS AND ACTION
Remember that the key you play is merely the
finished end of a piece of
wood (about 10" to 15" long) which functions as a lever, much like a
see-saw, in fact. It passes over a middle rail that is higher than its
front and back rails; thus when you press down on the key, the other
end pushes up on a series of levers and other moving parts called the action.
In a grand piano, the strings
are horizontal, and the keys and the entire action except for the
dampers is mounted under them. The hammer swings upward and strikes
the strings from below, while the dampers
are situated above the strings and fall by gravity to dampen them when
the key is released. To see an animated graphic of the grand
piano action, courtesy of MusicPlay.com, click
here.
In an upright piano, the
strings are vertical, and the keys and action are mounted alongside
them. The hammer is in a generally upright position, and swings
toward the string from the side, while the damper, mounted just below
the hammer, is powered to dampen the string by means of a spring:
Vertical pianos traditionally have been built in
four sizes, listed from shortest to tallest: (1) the spinet is the shortest vertical,
generally about 36 inches tall; (2) the console, about 42 inches
tall; (3) the studio
upright, about 48 inches tall; and (4) the full upright, 52 inches and
taller. Among verticals, the major difference in addition to
soundboard size and string length is the placement of the action.
In spinets (below left), the action is placed
partially below the level of the keys, and is attached to the keys by
means of a lifter wire which pulls up on the whippen to activate the
mechanism. In all three of the larger sizes, with a few
exceptions (below right), the
action is generally mounted completely above the keys and the
whippen is pushed upward by the key.
Whether the piano is a grand (i.e.,
horizontal) or an upright (i.e., vertical), the function of this action or mechanism is 4-fold (see
the named parts
in the illustration
below):
- To activate the hammer, a felt-covered piece of wood
that produces sound by striking the string to set it vibrating. The
hammer is set in motion primarily by means of a lever called the jack.
- To get both the damper and the hammer away from the string, thus
allowing the string to vibrate freely. This is accomplished primarily
be means of the regulating button (which moves the jack out of the
hammer's way) and the backcatch (which catches the hammer as it falls
back from the string).
- To dampen, or stop, the vibration of the
string after the player lets up on the key. This is done primarily by
the damper lever and damper head with its soft felt pad.
- To prepare itself in a split second to repeat
the above steps. This is done by a series of springs, by a special part
(in grands only) called the repetition lever, and by the overall force
of gravity helping to pull all the parts back into their original
position.
THE STRINGS AND TUNING PINS
Now assuming the mechanics work correctly (and
now that you're
thoroughly confused),
the strings will take over. Each string is a piece of extremely high
quality
steel, and each key or note has three strings (only two or one for the
lowest
notes). Each one is tightened to a tension of about 200 pounds
(imagine
a 200
pound man hanging from each string!) Multiply this figure by 200, the
approximate
number of strings in the piano, and you get a total of approximately 20
tons--thus the
need for the metal plate that makes up nearly half the weight of your
piano.
 
Clockwise from left to
right: (1) side view of pins in the laminated maple pinblock; (2)
strings crossing over the bridge; (3) metal plate with strings and
bridge; (4) soundboard and bridges with plate removed
THE BRIDGES AND SOUNDBOARD
Now, let's assume your keys are moving freely;
your action is in
working order
and is adjusted properly; and your hammer is "voiced" to its perfect
hardness. At this point something must amplify the string so it can be
heard.
This is the job of the bridges and soundboard. Without them, the
vibrating string would scarcely be louder
than
a rubber band stretched between the fingers, or an electric guitar
without an
amplifier.
The bridge is a piece of maple about one inch
square and running the entire length of the piano. Its purpose, in
addition to holding the strings in position, is to transfer the
vibration of the string to the soundboard. The soundboard, in turn, is
a large, thin piece of soft wood about 1/4" thick and covering the
entire inside area of the piano. It works like a big diaphragm, much
like your own eardrum, to vibrate at the same pitch (or frequency) as
the string, thus amplifying its volume.
If this final component is free to vibrate
properly, it is the final step in producing the magnificent sound only
a piano can produce. Now it needs only one last ingredient: something
to transform its sound into music. And this is something no technician
alone can offer--here we must turn to you, the pianist.
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