Tag Archives: Piano Design

Pianos Inside Out – Cover to Cover p1-50

fp-eev-secret-surgeryThis is part one a of a ten part series guiding us through the book Pianos Inside Out by Mario Igrec.

Okay! Its time to start reading! The first section we’ll address is pages 1-50. That’s Chapter 1 on History and half of Chapter 2 about Design and Construction. The goal is to read through this in one week. This section covers the beginnings of what is considered the modern piano and some variations along the way. Then we move on to the composition of the piano, including its supportive structure, strings, bridges and soundboard. The remaining structure is covered in the next section.

Here is a brief outline of the content of these pages, followed by some study questions. You can use this to prep before reading or review afterwards. Keep in mind that many of the study questions can only be answered by reading the text of the actual book. So dive in.

Chapter 1: History

The piano was born in 1700 when Bartolomeo Cristofori, of Florence Italy, installed the first piano action into a harpsichord. The purpose was to alter the instrument so that strings could be struck by hammers instead of plucked by plectra. This allowed for variability in volume depending upon how hard keys were pressed.

Around the same time a similar instrument was becoming popular called the pantaloon. It was a dulcimer modifies such that, again, strings could be struck by hammers, this time  instead of by the traditional dulicimer mallets. The instrument was named after a famous dulcimer player called Hebenstreit Pantalon.

Throughout the remainder of the 18th century, pianos grew in popularity, spread to various european locales, and were modified in several ways. The 1700’s saw the introduction of pedals, for example. Vertical pianos evolved from the clavicytherum, a type of upright harpsichord. In the latter half of the 18th century, the industrial revolution began to influence piano design and construction.

As the century turned even more advances in technology and a rising middle class meant that more pianos could be constructed and sold. Pianos began to be built in the United States. Bach, Haydn, Mozart and Beethoven all had the chance to interact with the developing instrument and as the 1800s progressed an increasing number of compositions were intended for the piano.

Through the first half of the 19th century the piano gradually became bigger and louder instrument. The range of the keyboard increased from 5 octaves to 6.5. The cast metal plate was introduced. The double escapement action was invented by Sebastien erard. The overall tension held within the instrument increased. Inventions and patents to improve the piano proceeded at a rapid pace. Agraffes, cross-stringing, the capo tasto bar, felt hammers, and technologies to aid in manufacturing things like hammers were all patented, introduced in this time.

In the second half of the 19th century Steinway began in America and then after success there began manufacturing in Europe as well. Also at this time the square piano became popular but quickly lost favor because of many design flaws. As the 20th century approached, pianos became quite a popular instrument, and very profitable to manufacture and sell. Popularity continued to grow in the early 20th century. However, as the phonograph, radio, motion picture, and television industries invaded, and because of the great depression and WWII, the piano lost some favor. Since WWII piano popularity has had swells within various markets independently, such as in Eastern Europe, Japan, Korea and China.

 

Chapter 2: Construction and Design

According to Mario Igrec “piano design history has been a struggle to more efficiency convert a finger’s force into acoustic energy.” This can be achieved through a number of manners: increased string tension, soundboard tension/compression, and mass of hammers.

In this section we learn about the integral parts of a piano: rim, beams, belly rail, pin block, stretcher, keybed, soundboard, soundboard ribs, long bridge, bass bridge, shelf, plate, strings, beams, nose bolts, Steinway bell, tuning pins, pin block, bridge pins, capo tasto, agraffes, plate flange, pressure bars, etc.

The rim of the piano consists of an outer and inner part. The outer rim is essentially a part of the case of the grand piano. There are two manners of constructing the rim. Composite rims are constructed from small segments and continuous laminated rims consist of a series of laminated boards that are all at once bent around a mold to form the shape of the pianos case. The rim of a grand piano supports its structure just as vertical beams in an upright do the same. A dense and rigid rim or frame maximizes volume and sustain.

Beams of spruce join a rim/frame with the belly rail. The belly rail provides a rail of support to which the soundboard can be glued.

The pin block consists of laminated sheets of wood with grans sequentially angled at 45-90 degree differences to one another. The pinblock must grip tuning pins firmly and transmit the tension of the strings to the plate and rim. A pin block is generally 1.25” to 1.5” thick [31 to 38mm]. In a grand piano a pinblock can be installed in 3 ways. In order of increasing quality you can have a floating, regular fit or full fit pinblock. Each style adds an extra point of structural attachment to the plate, rim, and stretcher respectively.

The strings, bridges, soundboard and plate generate sound. Each of around 230 strings – holds around 160-200 lbs of tension. Strings are typically made of high-carbon steel and sometimes nickel plated. Bass strings have a copper winding, to allow for increased mass (slower oscillation) without unmanageably thick strings.

The bridge lies compressed between the strings and the soundboard and transmits vibrations between the two. A stiff soundboard reflects some energy back the strings, which allows them to sustain longer. The bridge has often has a separate root and cap portion. A separate cap can be shaped and notched easily and replaced if it cracks. Bass strings are longer and extend toward the edge of the soundboard where it is more rigid. In order to increase flexibly in the area where the bass resigntes a shelf sometimes used to allow the longer strings to contact a more central (flexible) part of the soundboard.

Bridge pins are made of steel, often with brass plating to reduce friction. Notches in the bridge allow strings to vibrate freely where they contact the bridge pins. If notching does not create the same termination point at the bridge pin and the bridge notch this can lead to false beats. Sometimes termination points on the bridge are engineered to create unequal speaking lengths. Unequal lengths cause slight interferences among the sound waves from each string. This means the strings resonate with one another less effectively, transfer energy to the soundboard less effectively, and therefore can have a longer sustain.

The soundboard is sometimes mischaracterized as an amplifier, when in fact it is only a transducer of vibrations from the strings into the air. A good soundboard will effectively impede the vibrations of the strings, allowing for a short attack sound and a long sustain. A well designed soundboard’s resonances will be carefully tweaked so that the tone quality from the various strings in the piano is consistent. Spruce soundboard material is rigid along its gran but less so across the grain, therefore soundboard ribs are installed across the grain to create an isotropic diaphragm, in which rigidity is relatively equal in all directions.

The next post continues to work through chapter 2 on design and construction.

Study Questions:
(Many can only be answered by reading the text of the actual book. So dive in.)

pages 1-10:
1. What year marks the invention of the piano?
2. Who is credited with inventing it?
3. In which century were JS Bach, Haydn, and Mozart prominent? Which of them had the opportunity to use the invention of the piano?
4. There was an instrument called the Pantalon. Where does the name come from?
5. In what country was the piano invented?
pages 11-20:
6. Around what time did pianos start to be made in America?
7. What major development in piano construction allowed for louder pianos?
8. Around what year was it developed?
9. Who invented the agraffe in 1808? What other major invention is he responsible for?
10. Piano design history has been a struggle to do what?

pages 20-30:
11. According to Mario Igrec, what are the two most valued characteristics in pianos today?
12. The quality of these two characteristics is proportional to what?
13. True or False. The outer rim can be added after pin block, soundboard, bridges and strings.
14. What type of wood might you find in the dense rim of an expensive pianos?
15. What re the two main types of rims? How are they constructed

pages 30-40:
16. How thick is the typical pin block?
17. When bridges transmit vibrations from the strings to the soundboard, but also reflect much of that energy back to the strings, what tonal outcome does this create?
18. What is described by the following statements? Easier to shape and notch than a vertically laminated root. Can be replaced if it cracks. Can be used to modulate the stiffness of the bridge.
19. Which piano maker patented the continuous curved bridge?
20. What is described by the following statement? There are three types: regular floating, fit, full fit. Which is best?

pages 40-50:
21. What is the purpose of a bass bridge shelf or apron?
22. What is the purpose of having unequal speaking lengths in unisons?
23. How will a lower cutoff frequency in its soundboard improve a piano’s sound?
24. Which is a more appropriate term for the soundboard? Transducer or amplifier? Why?
25. What is a typical number of degrees for downbearing?

Here are PDF excerpts from various chapters of this book, hosted on the book’s web page:

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