How is a good piano produced?

This question is too big. I'll try to answer it simply.

Brief process of piano manufacturing

Timber structure member

1. Material selection of soundboard

The sound of the piano does not come directly from the vibration of the strings, but is radiated through the soundboard. So the volume and timbre of the piano depend on the quality and performance of the soundboard. The soundboard is the loudspeaker system of the piano, and it is also a vital part. The best castanet tree species in China is Picea Lijiang.

. The acoustic characteristics determined by the inherent microstructure and macroscopic characteristics of Picea crassifolia, a series of physical, mechanical and acoustic scientific experiments on the diameter cutting wood of Picea crassifolia, and the research on the design principle and music spectrum specification of this instrument all prove that Picea crassifolia wood is the most perfect musical instrument * * * with its quality, performance and taste far superior to other tree species.

2. Sound board manufacturing

Processing piano soundboards can be divided into solid wood soundboards and composite soundboards. The manufacturing process of modern large-scale professional sound board factory is as follows:

Let the wood dry naturally and permanently first, and then select it through many processes to adapt it to any harsh climate and environment.

Solid wood soundboard is made of radial cut wood of AA and A grade spruce. According to strict standards, the species, density, texture, color difference, acoustic performance and moisture content of wood are selected by manual multipoint and instrument testing, the soundboards are matched according to the design specifications and angles of soundboards, and the environmentally-friendly plastic glue is used for splicing.

The core board of solid wood composite soundboard adopts all kinds of spruce from all over the world, adopts integral forming and thickness fixing technology, and is spliced with polyurethane plastic; The surface layer is the radial cutting veneer of oblique AA spruce, which is glued at low pressure and low temperature to ensure that the wood has no pressure loss and maintains its natural advantages.

The composition adopts an anti-aging plasticizer environment-friendly adhesive formula. The unique product structure and process method not only meet the performance of traditional solid wood soundboard, but also highlight the advantages of balanced strength and good weather resistance in all directions. Castanets are explosive and have lasting vitality. Different splicing methods and product grades are suitable for all kinds of pianos. The main varieties are: vertical, horizontal and diagonal wood composite soundboards with equal or unequal core thickness.

At present, the products of piano factories, including world-famous piano manufacturers, widely use composite soundboards, which have high strength and are not easy to crack and deform in different geographical environments.

3. Piano ribs

There should also be ribs on the back of the soundboard. The function of the ribs is to bear the pressure of the strings on the soundboard to enhance the elasticity of the soundboard. Ribs can also transmit sound to all parts of the soundboard, making the soundboard emit * * *. Generally speaking, the number of ribs is about 65,438+00, which depends on the area of the soundboard. Ribs are made of all kinds of spruce in the world.

4. Sound board assembly

Exquisite spruce soundboard and ribbed wood are made by heating and pressing with high-frequency medium of environmental protection glue. The assembly adopts "prestressed arc technology", which makes the sound board vibrate more freely and ensures the piano's timbre to be more beautiful and pleasant. The soundboard is curved, not flat, similar to the upper cover of a guzheng.

The front of the soundboard is glued with chord codes. The function of the chord code is to transmit the vibration of the chord to the soundboard, and the chord code is also equipped with a pin for fixing the chord position.

5. Shell and supporting structure

The shell of the piano includes a top cover, a keyboard cover, an upper door panel, a lower door panel and side panels. The function of the shell is to stabilize the keyboard machinery, pedal machinery and string structure, prevent dust from entering and ensure that internal parts are not damaged. In addition, it can increase the volume and make the timbre more pleasant.

Since Steinway successfully used plywood to make piano shells in 1880, this method has been widely used by piano factories all over the world. At present, almost all pianos are made of plywood, which has little influence on piano timbre and has the advantages of strong weather resistance and difficult deformation. The colored pianos we see with wood grain are usually coated with a layer of wood skin or colored paper. Piano paint is high-grade resin paint, which can be divided into bright and matte. The bright color is generally black and red, and the matte color is generally wood color. Bright light is easy to maintain, and matte makes the piano more noble and elegant.

support

The bracket is the skeleton of the whole piano, and its function is to firmly support the taut strings and stabilize the soundboard, keyboard mechanism and shell.

The bracket consists of an iron frame and a back frame. Because steel has the elasticity of compression deformation, it will make the piano pitch unstable. Therefore, the iron frame is not made of steel, but cast with pig iron, with high hardness and no deformation. Its function is to strengthen the tension of strings, so as to obtain crisp and rich sound. The iron frame and the back frame are firmly combined with bolts to support the tension of the whole string. The tension of each string is about 80 kg, and the whole iron frame is harmonious. Cast iron frame can be used for assembly after grinding and painting. The back frame is made of hardwood, and the upper and lower ends are glued with beams, the middle is glued with square wood, and the upper beam is glued with chord plates.

The chord plate is an important part of the back frame, and its function is to fix the chord. Under the tension of chords, any loosening of chords on the chord board will affect the pitch. In order to prevent chord deformation, the chord board in upright piano is generally made of 3-5 layers of hard maple.

Chord array

The main body of piano pronunciation is the strings. The function of string array is to make the strings vibrate at a certain frequency. No matter what kind of piano, the strings are arranged from low to high, with long and thick bass and short and thin treble strings. In order to obtain low-frequency sound, the bass area is wrapped, and the treble area and the midrange area are exposed. In order to increase the vibration area of the strings, the strings are arranged crosswise at the junction of the midrange and bass.

The modern piano has 88 or 85 keys (depending on the size of the piano), that is, it contains all 88 or 85 tones of the musical system. However, this does not mean that the piano is composed of 88 or 85 strings. The number of strings is about 2 17. Most of the piano sounds are composed of three strings, and only the bass is composed of 1.

The upper end of the string is wound on the string shaft, the string passes through the string pillow, then passes through the pin on the string code, and the lower end is sleeved on the hanging pin. In order to make the vibration frequency of the harmonic string group consistent, a string presser is added between the chord axis and the piano pillow in the midrange and treble areas, but there is no such device in the bass area. The vibrating part of the string is between the upper pin and the lower pin.

Chord codes and frets also play an important role in sound propagation. The sound produced by string vibration alone is relatively weak. The strings transmit their vibration to the soundboard through the sound posts and codes, and then generate * * * sounds through the resonance of the soundboard, so as to increase the volume and prolong the sound.

In addition, the pitch of the piano depends on the tension of the strings, and the tension is influenced by the chord axis and chord code. If the chord axis is loose or the chord code is broken, the vibration frequency of the strings will be reduced, which will directly affect the pitch.

Piano strings. In order to use high-quality fine steel and copper that meet the acoustic requirements, the piano steel wire is imported from abroad.

Second, the keyboard machinery-keyboard

Keyboard machine is the heart of the piano, it is a lever system, which consists of two parts: keys and percussion machine. One end of this lever system is the key and the other end is the hammer. Through this lever, the playing force of fingers on the keys is transferred from the hammer to the strings, making the strings vibrate and pronounce.

1. Keyboard

The sum of these keys is called a keyboard. There are 85 or 88 black and white keys keys on the keyboard (black keys 36, white keys 52). The keys are arranged in the order of chroma difference, and * * * is divided into seven multi-word groups (from A in the second group of big characters to C in the fifth group of small characters). Every 7 white keys and 5 black keys constitute 1 sound group.

A keyboard consists of a keyboard frame and keys. The keyboard frame is under the keys. The keyboard frame consists of three sleepers and several longitudinal beams. Two rows of elliptical pins are on the front sleeper, and reasonable rows of elliptical pins are used by White Key and black keys respectively. When the key becomes loose or tight, it can be adjusted by rotating the oval pin. The round pin on the middle sleeper is used to fix the range of motion of the keys. In order to make the performance quiet, let the keys go up and down.

Keys are divided into solid wood keys and combination keys. Solid wood keys are made of natural wood, and the strings are cut without joints. The density, chord shear rate, texture, stress line, color difference, dimensional stability and moisture content of wood are all selected according to strict standards through manual multi-point selection and instrument testing. The planned size of the slat unit is 60- 140mm, and the combination keys are cut radially without seams according to the design specifications of the keyboard board.

The end of the keyboard glue with black and white keys leather is the front end, and the end with metal nails (called clips) is the back end. Black keys leather is mostly made of hard plastic, while white key leather was originally made of ivory. Since the entry into force of the United Nations Convention against Ivory Trade, they have all been made of polymer materials such as acrylic acid. The opening in the middle of the bottom of the keyboard is glued with loose hair, and the round needle is inserted from here. The bottom opening at the front of the keyboard is also glued with loose wool, and the oval pin is inserted from here. keyboard

Keyboard machinery. Stringer.

It is the main component to combat the vibration of strings. It consists of four parts, namely, chuck, stop, hammer and contraction tuning, which are mutually restricted and related. Stringer is the most complicated mechanical part in piano structure, which requires the highest reliability. Generally, it is manufactured according to the technical specifications of Renault in Germany and Lange in Britain.

The working state of the string striking machine is as follows: when the key is pressed, the clamp at the back end of the key will push open the chuck, and the ejector of the chuck will move upward to push the hammer to rotate the machine, so that the piano can hammer the strings. When the hammer is about 5mm away from the string, the protruding part of the ejector will contact with the contraction sound, and at the same time, the ejector will leave the hammer, and the rest of the "journey" will be completed by the inertia of the hammer, and the hammer will return quickly after striking the string. Stop the sound and leave the string, then the hammer hits the string, and the string vibrates freely to make a sound. When the key is lifted halfway, stop starts to stop. When the key is completely lifted, the whole machine is completely restored to the static state.

Hammer is generally made of Australian wool, and the surface is coated with two-color moth-proofing agent, which has soft and elastic tone and long service life. The internal stress of the hammer directly affects the timbre after striking the string. The duration of striking the strings will affect the timbre produced by the strings.

The principle is that the sound produced by strings consists of pitch and overtone. The shorter the strings are hammered, the more dissonance and overtones are excited, and the timbre is hard, bright, explosive and harsh. On the contrary, the longer the hammer hits the strings, the less dissonance and overtones are excited, and the timbre is soft and pure.

The difference of timbre between gravity playing and light playing on the same piano, or different touch methods (fingers vertical or not) make the piano meet the requirements of music with different characteristics and emotions. Controlled by the player

The internal stress of the hammer will also directly affect the hitting duration. Generally speaking, the harder the hammer is, the shorter the hitting duration, and vice versa. Adjusted by a lawyer.

As early as 1730, shortly after the piano came out, factories specializing in making rap machines appeared in Europe. At present, most of the rappers used in piano factories all over the world are purchased from professional rappers, which are of higher quality and lower cost than the piano factories themselves.

In China, there is also a world-advanced professional string-playing machine factory. At present, piano factories in China, large and small, also buy percussion machines for assembly rather than making them themselves. However, in the early days, the percussion instruments of various piano factories were all made by themselves. Some of them felt hard, the surface was smooth and hard, the sound was too hard, explosive and smelly.

The sound of the old piano exploded because the hair and sticky tissue on the contact surface between the hammer and the strings were hard, which was also called "too bright". Need to be adjusted.

Pedal system and adjustment

The function of the pedal is to change the sound intensity, * * * and prolong the sound. A pedal machine consists of two or three pedals and a series of levers. The working state of the pedal machine is: when the right pedal is stepped down, all stops are raised, so that the strings that have not been hit ring * * *, enhancing and prolonging the volume and beautifying the timbre; When stepping on the left pedal, the distance between the hammer and the strings is shortened by nearly half, the number of times the hammer hits the strings is reduced, and the volume is weakened; When stepping on the pedal, the board with woolen cloth on it will fall off, and the hammer will knock the strings through the woolen cloth, making the volume weaker. Generally, it is necessary to avoid disturbing neighbors at night and reduce the playback volume.

After the piano is manufactured, it is also conditioned through the whole sound production process, so that the tone and feel of the piano are better and the expression is more perfect. Maintenance of Piano The daily maintenance of a piano composed of nearly ten thousand parts is very important.

1, keyboard

First of all, when playing, gently open the piano cover, don't scratch the keyboard, and don't strike the keys hard to avoid damaging the internal parts. Don't pedal too hard or too hard. Don't put sundries on the keyboard, so as not to fall into the gap, which will cause the keyboard machinery and other machinery to fail, and don't put hot water containers on the piano, so as not to burn the paint on the piano surface or splash it into the piano, which will cause the internal parts to rust.

2. Hygiene

The inside and around the piano should always be kept clean to prevent dust from falling into the piano and reduce the sensitivity of the machine. Some mothballs (essence) can be wrapped in gauze, placed in the gap under the keyboard and hung on the screws on both sides of the beating machine. This can prevent the felt in the piano from being eaten by insects.

3, moistureproof

Excessive temperature will damage the piano. Keep the piano away from any place with direct heat and avoid exposure to the sun. If you put it by the window, keep a certain distance to avoid too direct exposure and reduce humidity. Humidity will rust the strings, expand the wood, and make the crowded keys inflexible. The ideal humidity of piano is 20-22(68-72F).

The piano is best placed in a room with moderate humidity, not too close to the wall or too far from the door. If the weather is too dry, you can sprinkle some water indoors to improve the indoor humidity. If the indoor floor is very wet, or you can put a wooden board under the piano, you can also open the lower cover plate and install a moisture-proof pipe inside the piano to adjust the humidity with the heat emitted by the moisture-proof pipe.

Step 4 clean the piano

In addition, it is best to use flannel when cleaning the piano to avoid rubbing with alcohol, which will cause cracks in the piano paint turtle. You should be very careful when you move the piano. You'd better lift it and move it steadily. The shell of the piano can be rubbed along the wood grain with a soft cloth according to its material and the maintenance method of furniture. Wipe the keys with a slightly wet surface or sponge. Too wet cloth will make water flow into the piano. Please ask Andhadhun to clean the inside of the piano while tuning.

5, pest control, rat prevention

Preventing moth-eaten is an important part of piano maintenance. Putting sanitary balls or camphor essence in the piano can only be effective for a short time. The best way to prevent moth-eaten is to put a mixture of borax (200g) and bhc powder (50g) in the piano. Installation method of powder: upright piano can be sprinkled on the middle board and chassis. Grand piano can be put into a bag and placed on both sides of the piano near the chord axis, which can keep insects free for about 10 years.

The average life of the piano is 40 years, which is more durable than most furniture in the house. It should be properly maintained. The sudden change of temperature and humidity is a taboo for piano maintenance. If the relative humidity is 40-6…%, adjust the indoor humidity and humidity if necessary. Warm pipes can be installed in the piano to reduce humidity. Another enemy of the piano is insects. Many parts of the piano are filled with felt and leather, which is the favorite food of Duchang insects. Some insect repellents can be packed in gauze bags.

6, regular tuning maintenance

The main sound of the piano is a wooden soundboard with nearly 220 strings and a cast iron frame connected to it. The tension of each string is about 80 kg, and the total tension of all strings borne by the whole iron frame and soundboard is about 18 tons. Because the strings, the iron frame and the soundboard are elastic, the strings become a comprehensive elastic body after being tightened, and the internal stress is great. Under the impact of the hammer, the strings and elastic bodies vibrate regularly, producing pleasant music. Because the comprehensive elastic body itself has great internal stress, it will be affected by temperature, humidity, air pressure, etc., and it will constantly vibrate and sound, so it is always in a continuous change. If this change is not standardized and corrected, let it be.

A, keep the balance of endurance: the piano sometimes breaks a string. If not replaced in time, more strings will be broken one after another. This is because the comprehensive elastic body is out of balance and the internal stress changes. Therefore, it is necessary to tune the piano according to the seasonal changes, and ask the piano technician to deal with it in time according to the situation of out-of-tune and broken strings to restore the balance of the comprehensive elastic body.

B. Objectivity of unstable factors: When the piano is in frequent tapping movement, it will naturally cause repeated Zhang Chi to the soundboard of the strings and gradually change the pitch. In particular, the strings of the second group of small characters are the most commonly used parts, and most of the melodic sounds are in this section, and the string code tension of this section is located in the most unstable sensitive area in the middle of the soundboard, and the off-key often appears in this section.

C, the basic guarantee of timbre: Because piano sounds mostly use two or three complex strings, even if the vibration frequencies of the three strings are very consistent, as long as you play for a short time, you can immediately determine that the frequency between strings has changed subtly, and then there will be vibrato in different degrees. It is precisely because the piano with complicated strings requires the same degree and tries to keep the pitch pure, which is why the piano needs to be tuned regularly.

D, the tuning time of the new piano The newly bought pianos are basically high in pitch when they leave the factory. Affected by external vibration and climate change after transportation, it will inevitably cause various changes. In order to make the internal stress transition and adapt to the new environment, the new piano can be used for one or two months before debugging. In this way, the stability performance will be more reliable.