|
BUYING SAFELY
1. A piano is a
stringed instrument.
2. Strings are pulled to high tension.
3. The back posts and the cast iron plate work in concert to support
the tremendous tension of the strings.
WHY:
Here are the reasons why
it is necessary to have the strongest structure possible to support
string tension:
* To prevent
the back of the piano from warping and twisting.
* To enable the piano to stay reliably in tune
between tunings.
* Without solidity in the structure the many parts of
the piano could not function properly.
THE BACK POSTS:
1. Look at the back of the
piano first, the back posts are easy to see on most instruments.
Notice the following things about the back posts:
* Size of the
post; not only width, but depth.
* Double, triple, posts - wood grain appearance
* Post extend to the top of the piano.
* Posts extends to the bottom of the piano.
WHY:
1. A piano is a
stringed instrument.
2. Strings are pulled to high tension.
3. The back posts and the cast iron plate work in concert to support
the tremendous tension of the strings.
These are the
reasons why it is necessary to have the strongest structure possible
to support string tension:
* To prevent
the back of the piano from warping and twisting.
* To enable the piano to stay reliably in tune
between tunings.
* Without solidity in the structure the many parts of
the piano could not function properly.
MATERIAL
USED IN BACK POSTS
SOLID SPRUCE:
* Because its
the strongest wood for it's weight.
* Resists splitting and cracking.
* Spruce's lengthwise grains are straight,
close and dense which provides rigid support.
* Posts are bolted to cast iron plate.
WHY:
1. A piano is a
stringed instrument.
2. Strings are pulled to high tension.
3. The back posts and the cast iron plate work in concert to support
the tremendous tension of the strings.
These are the
reasons why it is necessary to have the strongest structure possible
to support string tension:
* To prevent
the back of the piano from warping and twisting.
* To enable the piano to stay reliably in tune
between tunings.
* Without solidity in the structure the many parts of
the piano could not function properly.
EXCEPTION TO THE RULE:
As mentioned, some
pianos will have metal back posts, others, will have
virtually no wood back posts at all. Many high quality
pianos have scale designs which provide plates that
have rigid I - Beam like construction that extend to
all four corners of the frame, which actually adds
the strength of two or more back posts. This is an
expensive process known as a full perimeter plate.
This is also an acceptable method. Astin Weight - Ibach - Knight
- Some Kawais - Some Yamahas - Some Webers - to mention a few.
TUNING
PINS AND PIN BLOCK
1. The purpose of
the pin block is to firmly hold the tuning pins in
place where the strings are attached.
* Tuning
pins vary in quality.
* Better grades of tuning pins have machine cut
threads.
* Tuning pins should be "blued steel",
an electronic method to prevent rust.
* Nickel-plated steel tuning pin.
2. The pin block
in many of the finest pianos in the world
consists of several plies of hard rock maple.
Alternate plies have grain running at ninety
degrees to that of adjoining plies to assure even
gripping of the pins, and to prevent splitting of
the pin block.
* Material
of pin block should be hard rock maple.
* Wood should be quarter sawn for strength.
* Pin block should be at least 2" thick.
* Number of plies not as important as type and
cut of wood.
THE
HAMMERS - THE
QUALITY OF THE HAMMER:
This is another area where you can
visibly see quality. Are the hammers nicely spaced. Are they all in
line. Good pianos in a
console size use about a ten to twelve pound hammer.
Piano hammers are made of fine wool felt which is
formed around a hard-maple hammer molding.
First-grade piano hammers are made of two layers of
felt; the outer layer is white, the inner usually
purple, green or magenta.
The layers of felt
are applied separately. The forming and gluing of the
felt to the hammer is done with tremendous pressure
applied by hammer presses. Many tons of pressure are
applied from several angles, forming the shape of the
hammers.
The result is one
long piano hammer which is then cut into individual
heads. Holes are bored at the proper angles on the
underside of each head, into which the hammer shanks
are later glued. Each set of hammers is then
individually and painstakingly fitted to the piano.
Some hammers are stapled, others have a cotter
key-like wire through the hammer to insure stability
in the hammer. Many imported pianos have hammer
weights of up top twenty pounds on grand pianos.
One of the least
understood and most controversial subjects in the
world of pianos is hammer weight. The prospective
buyer is told that one piano has twelve-pound
hammers, while another has only nine or ten-pound
hammers. A glance into the piano tells us that surely
those hammers, even all eighty-eight of them, do not
weigh from nine to twelve pounds. The figure refers
to the size of the felt sheets used in the making of
the hammers. The felt in an individual hammer
averages 109/l000ths of an ounce, depending on the
weight of the sheet of felt from which it was made;
and the difference between nine and twelve-pound
hammers average 36/l000ths of an ounce per hammer.
The important thing to remember about hammers like
all other parts of the piano, is that not only the
quality of the materials, but how those materials are
utilized in the building of the instrument determine
the overall quality of the product. In the case of
hammers, the proper shape and hardness are the key
factors affecting proper tone regulation. That's why
it is often said that while a good hammer can't make
a poor piano sound good, a bad hammer can spoil the
best piano.
THE
SOUNDBOARD
1. The soundboard
consists of a sheet of wood;
* One thickness
spruce (the term "solid" when referring
to spruce soundboards is very often misleading
today because some builders of pianos with
laminated boards where all three layers are
spruce, refer to soundboards as "solid"
spruce meaning they are all spruce).
* Special taper. Starting from 6 to 9mm at the at edges (3/8 of an inch thick and beveled)
as a resonator.
2. The soundboard
is not flat as it appears. but has a crown held in
place by a series of ribs. If the soundboard were
flat or if it were to lose this crown, there would be
very little volume or tone.
* The ribs are
made of a lightweight wood such as sugar pine,
are double notched and fitted into soundboard
lining. * They are tapered to fit and correspond
with the taper of the soundboard.
BRIDGES
The next step, and
one of the most critical in the making of a fine
piano, is the shaping of the treble and bass bridges.
The bridges, of Northern hard maple, must be planed
to exact thickness from end to end, so as to provide
the proper down-bearing of the strings upon the
bridges. It is this correct down-bearing which is so
vital to the transfer of the string vibrations to the
soundboard (resulting in pleasant piano tones).
Bridges should be
glued to the sounding board with hot hide glue and
further secured with wood screws from the back. Such
screws should have maple buttons under their heads.
The bridges must be accurately notched, at both top
and bottom in the case of treble bridges, for each
individual note. This provides for the
"stopping" of the string at a precise point
in much the same way as a violinist "stops"
his strings be fingering. Bass bridges are planed on
both edges for the same reason.
Bridges, made from maple, must
be planed to exact thickness from end to end, so as to provide the
proper down bearing of the strings upon the bridges, this is
measured by the use of a "bearing gauge" (See Glossary of Piano
Terms).
* Bridges
are glued and further secured to the soundboard.
* To prevent vibrations bridges are secured with
wood screws that have maple buttons under their
heads.
* Bridges are double notched.
* Bass bridge cantilevered.
A time and
money-saving way to do this important bridge notching
is to notch the treble bridge on the top edge only.
Half the work, half the cost and many piano buyers
can't tell the difference unless they are able to
distinguish subtle differences in piano tone.
THE
STRINGS
Every musical
effect in a piano must originate in the strings.
The soundboard, no matter how perfect, can only
amplify the sound produced by the strings. Pianos
have from 215 to 230 steel strings graduated in
length and thickness to produce the 88 notes of a
piano's scale design. The shortest string is
about 2", the longest string may be 84"
or longer.
The bass strings should be pure copper wound, not
plated.
* Examine the spacing of the strings
in
relation to other strings, spaced evenly
without touching another string.
* Depressing a key slowly, check
damper
alignment. At the same time, check as
hammer strikes the strings.
Check
to see if hammers strike all of the strings of all
notes.
Inspect the strings for even spacing (not touching
another string) and proper alignment with the
dampers.
Listen to the piano - Is the tonal output powerful
enough, at least impressive enough that you should
expect from a "classic" piano, but
capable, nevertheless, of filling a room no larger
than 15 square feet or of a volume not more than say,
2500 cubic feet ?
Is the tonal output reasonably mellow (very bright
indicates hardened hammers from age or dry climatic
conditions).
Is the
tone even and with a fair singing quality ?
Is the
action satisfactory, that is, does it give a fairly
elastic response to your touch ?
TEST
THE
PROPER WEIGHT FOR KEY DEPRESSION IS BETWEEN 2 AND
THREE OUNCES IN GENERAL. SIMPLY TAKE A SCALE SUCH AS
WEIGHT WATCHERS, OR THE POSTAGE SCALE AT THE POST
OFFICE. TAPE A FEW COINS TOGETHER, (NICKLES ARE OK ) OR GET A FEW WEIGHTS (FISHING TACKLE OK)
FIND A SMALL WEIGHT THAT WEIGHS AROUND 2 1/2 TO 3
OUNCES.. PLACE THAT WEIGHT ON ANY PIANO KEYBOARD
WHERE THE FINGERS PLAY AND THE KEY SHOULD DEPRESS.
THIS IS AN ACCURATE, BUT SIMPLE WAY TO TEST FOR
TOUCH, THE AVERAGE TOUCH IS AROUND 2 1/2 OUNCES.
THE ACTION
Briefly
stated, the way a piano action works is that the down
pressure on a key is converted to a forward motion of
the hammer towards the strings. The hammer travels
five times as far and approximately four times as
fast as the front end of the key does, the key travel
being only about 3/8 of an inch at its front edge.
This is accomplished through a remarkable system of
levers and pivots which, for a quality piano, must be
adjusted to the utmost accuracy, making the action so
responsive to the player's touch on the keys that
there is almost no limit to the musical effects
obtainable. For a better, more natural leverage,
piano keys slope slightly downward towards the back
and become level when the key is depressed.
A piano action
would be a fairly simple mechanism if, when you
depressed a key, it just had to push the hammer
against the string. But if it worked that way, there
would not be much tone because the hammer would stay
against the string and, acting as a muffler, would
stop it from vibrating. Thus, it would not have had
time to return to its starting position after you
released it.
Consider the
manufacturing problem created by the fact that
thousands of the parts in a piano are moving parts,
that many are very small and that on some of them a
variation of a thousandth of an inch will affect
their performance. Not only is the utmost precision
required in making and assembling the parts, but they
must operate quietly and resist friction, wear and
loss of accuracy under long and strenuous use. The
materials used today for the best piano actions are
largely wood, felt, woolen bushing cloth and leather.
Like all products of nature, these items are inclined
to be unstable when exposed to varying climatic
conditions, although this hazard is greatly reduced
in the better pianos by use of the highest quality
materials and by superior workmanship.
If metal could be
used, it would simplify the manufacturing problems
and substantially reduce the cost; however, metal
(not being noiseless without frequent lubrication and
adjustment) does not lend itself to the purpose and
very little of it is employed. Many other materials,
including all kinds of synthetics, have been tried,
but, with few exceptions, have not proved success,
imagine a hinge or bearing that would work smoothly
and silently for fifty years or more without
lubrication or constant adjustment. Every pivot in a
piano action must do this and they do it because
these moving parts are held in a circle of specially
made material called bushing cloth. Action hinges or
pivots are made by boring holes in wooden parts,
lining the holes with this bushing cloth, then
connecting the adjoining parts with German Silver
center pins which will rotate in these cloth bearings
indefinitely without attention unless exposed to the
most abnormal climatic conditions. This cloth, among
its many other properties, must be uniform in
thickness to an unbelievable degree. The makers allow
a tolerance of 2 one-thousandths of an inch, plus or
minus, which is less than one-half the thickness of
an ordinary business card and is an incredible
measurement for such material. It requires a total of
ninety-six different operations in the felt mill to
produce the superior grades of this cloth used in
actions.
To summarize the
story about piano actions, good performance is not
only a question of superior materials. but also
involves skill, experience and the willingness of the
piano manufacturer to spend the extra money to have
these important hidden parts as accurate and
dependable as it is possible to make them.
THE PEDALS
AND CABINET
Most piano
manufacturers offer three pedals. On most vertical
pianos the pedal to the right is a full sustain pedal
and by depressing it, the piano tone will linger on
or sustain the note. The left pedal is known as the
"Una Corda", which softens or limits the
power of the tone by moving the action forward and
limiting the distance the hammers travel. On a grand
piano it shifts the action slightly, enabling the
hammer to strike fewer strings.
A third pedal in
the middle varies from brand to brand. It may serve
to sustain the bass notes only, or it may act as
another form of soft. In some cases, it drops a piece
of felt to provide a muffler, or practice pedal.
On a grand, it
becomes a true "Sustenuto", that is,
allowing the pianist to sustain many notes as long as
the pedal is held. A good way to tell about the
quality of a piano is to hold a pedal in your hand
and get a feel for it. Twist it and push it, then go
to a more expensive piano and compare. You'll see the
difference in quality.
As a final point of
clarification, many very fine pianos in the world
only have two pedals, and for many years many
American pianos including Steinway only used two
pedals on many verticals. The center pedal on
vertical pianos is an extra feature which can be a
mute, a form of soft, or even a bass sustain. There
is nothing wrong with having two pedals on a piano.
For many years, that is all anyone had.
HOW IT ALL
WORKS IN CONCERT TOGETHER
Like the speaker of
a radio, a piano's sounding board is a vibrating
diaphragm. To work properly, the board must always be
under tension. This is accomplished by having the
center of the board arched, or crowned, with the
strings pressing down on the board where they cross
the bridges. The vibrations of the strings are thus
transmitted through the bridges to the sounding
board, where they are greatly amplified by the board
and projected into the air to reach our ears.
The piano string
acts as a tone generator. The sounding board's
function is to truly reflect and amplify that tone.
The sounding board is the most important single part
in the piano because if the board is bad, you do not
have a piano until there has been a major repair job.
No real music can come out of a conventional piano
except through the sounding board. So that it will
vibrate freely, a sounding board is necessarily a
very thin panel, usually from 3/16 to 3/8 of an inch
thick. Ribs are added to stiffen the board and to
help preserve the crown. The reason the ribs are
shaped at the ends is to allow the board more
flexibility around its perimeter. Until recent years,
all piano sounding boards were made of solid lumber
pieces glued edge to edge. Wood, however, has an
irresistible tendency to absorb or lose moisture
according to the humidity content of the surrounding
air. Absorption of moisture causes the conventional
sounding boards to expand, increasing the tension of
the strings and, thus, raising the pitch. Conversely,
the pitch is lowered when the board dries out. It has
been a constant struggle to try to keep such sounding
boards from splitting or from losing their
all-important crown. To obtain perfect musical
results, there must be good contact between each of
the strings and the board. This perfect contact
cannot be maintained if the board loses all, or even
part, of its convex form (crown). Piano sounding
boards are made of wood because no other known
material amplifies musical tones so well.
THE CABINET
The case is made of
veneers of oak, walnut, or other outer finish. It has
a core made up of cross sections of another yet
cheaper form of wood, pressed wood, or chipped wood,
which are totally acceptable in and by today's
standard because they are for cosmetic appearance
only and should not wear out..
Next, is the beauty
of case design and finish. The standard cases are
made or finished in mahogany, walnut, ebony,
rosewood, oak, fruitwood, pecan or pine. The two
first named are the more popular. All are dependable
if the piano is well made. The manufacturing process
for pianos does not readily lend itself to
automation, due to variations in the acoustical
qualities in pieces of wood. These variations require
skill in selecting the wood stock and conditioning it
to specific moisture levels. Many of the other labor
- intensive functions such as voicing, tuning and
regulation require skills based on years of
experience. For these reasons the piano is still
handcrafted in many respects.
Return to Main
Index
|
