Pianos
Last updated: February 27, 2008.
Who are the world's best musicians?
Everyone has their own personal
view on this, but for my money concert pianists win hands down.
If you've ever seen a world-class pianist playing a great piece of
music, like a Beethoven sonata, you'll understand exactly what I'm
talking about. It takes amazing physical, intellectual, and emotional
brilliance to play such a complex instrument in such a captivating
way—and only a tiny proportion of the world's pianists are up to the
job. But it's not just the musician who makes the music sound so
fantastic: the instrument plays a huge part too. Let's take a closer
look inside a piano and find out how it works!
Photo: On a high note. Unlike a traditional
mechanical piano,
this one makes its sounds by entirely electric means, so it sounds very
different.
Picture by Paul T. Erickson courtesy of the Defense Visual
Information Center.
How pianos make sound
Photo: Jazz musician Duke Ellington poses with
his piano at the KFG Radio Studio in 1954.
Picture by courtesy of the Defense Visual Information Center.
A piano sounds quite unlike any other instrument and, if you heard
it on the radio, you'd probably never guess how it was making a noise.
The confusing thing about a piano is that it's two different kinds of
instrument in one: it's a string instrument, because the sounds
are made with strings, but it's also a percussion instrument
(like a drum) because the strings make sounds when something hits them.
So what happens when you press the key of a piano? The key
is actually a wooden lever, a bit
like a seesaw but much longer at one end than at the other. When you
press down on a key, the opposite end of the lever (hidden inside the
case) jumps up in the air, forcing a small felt-covered hammer
to press against the piano strings, making a musical note. At
the same time, at the extreme end of the lever behind the hammer,
another mechanical part called a damper is also forced up into
the air. When you release the key, the hammer and the damper fall back
down again. The damper sits on top of the string, stops it vibrating,
and brings the note rapidly to an end.
How a piano works: Press down on a key and you make a small hammer shoot up and strike the corresponding strings from beneath. Release the key and the damper at the back falls down onto the strings, stopping the note. Note that this is a hugely simplified version of what happens. The hammer and the damper are actually controlled by much more intricate mechanisms than this. You can see just how intricate by looking
at the Schematic of the Steinway Model M Grand Piano on the Steinway website. This artwork shows the action mechanism (which plays the notes) in full detail.
Getting louder
If that were all their were to a piano, no one in the audience would
hear very much. So there are lots of other parts in a piano designed to
make notes sound louder or last longer. The strings of
a
piano stretch out horizontally away from the pianist sitting at the
keyboard, just as though a piano were a guitar laid flat on its back.
When you pluck a string, it vibrates, sets air molecules in motion and
sends the sounds of the strings out toward your ears. To make the
sounds louder, there is a large piece of wood mounted underneath them,
called the
soundboard (or sounding board). When the strings
vibrate, the soundboard also vibrates in sympathy (resonance), just as
a wine glass vibrates when a soprano sings a high note nearby. The
soundboard effectively amplifies the strings so they are loud enough to
hear. The
lid helps the audience too: sound from the strings
and the soundboard travels straight up, hits the lid, and reflects out
toward
the audience. That's why it's always better to sit on the right of the
pianist and why concert hall seats to the left of (and behind) the
pianist are generally much cheaper.
Photo: Looking from
the back of a piano, under the lid and into
the case, you can see the strings stretched taut across the sturdy
cast-iron frame. The long bass strings are on the right in this picture
and the shorter treble strings are on the left. The open lid reflects
the music into the audience like
a giant, wooden sound "mirror".
Picture adapted from an original photograph by Marie Cassetty courtesy
of the Defense Visual Information Center.
Pedal power
While the 88 keys on a piano control the musical notes that the
pianist can make, the three pedals determine how loud or soft
these notes are and how long they last. The pedal on the left is called
the soft pedal. Most of the keys on the keyboard hit two or
three strings simultaneously when you press them, so you get a richer
and louder note. However, if you press the soft pedal down, the hammers
that play the notes shift slightly to one side so they contact fewer
strings—making a quieter note. The middle pedal is called the sostenuto
pedal: when you press it down, it temporarily deactivates the
hammers for the notes that you're playing at the time, and makes them
last quite a bit longer. The pedal on the right is called the sustaining
pedal. Pressing it down raises all the hammers up in the air so all
the notes last longer.
Photo: In an upright piano, like this vintage
Steinway, the strings run vertically at the back of the case and the
hammers strike them by moving horizontally. It's like a grand piano
standing on its end—literally upright. This particular instrument spent
22 years entertaining naval personnel stationed onboard the nuclear
submarine USS Thomas A. Edison.
Picture by courtesy of Steinway & Sons
and US Navy.
Strings and things
If you've ever wondered why pianos are such a funny shape, that's
easy to answer too. Remember that they're string instruments. Lower
notes need longer strings than higher notes, so the bass strings
for the low notes on the left-hand side of the keyboard need to be much
longer than the treble strings for the high notes on the
right-hand side. That's why the case is longer on the left than on the
right and why it has that funny curved rim. In fact, the
strings on the left are so long that they cross over, on top of the
middle and treble strings to save space. (Take another look at the photo up above.)
Since each note can have up to three strings, it turns out that
there are well over 200 strings inside a piano—each one stretched
really tight. To stop the strings from collapsing the entire piano
inwards, the rim and case are reinforced by a huge, heavy cast-iron
plate. The plate sits just above the sound board and large metal
holes around its edge (known as rosettes or portholes)
allow the sound to come up through it.
That's a very quick tour of a piano, one of the world's most amazing
instruments. If you want to find out more, take a look at a brilliant
book called
Piano: The Making of a Steinway Concert Grand
by James Barron. It's a very readable little paperback that describes the
fascinating story of how one Steinway piano was put together, starting
from the forest that supplied the trees and ending in the concert hall
where the instrument made its musical debut.
