How can the piano "inner" set off "waves" by Zhou Dong and Lang Lang?

Piano

The agile fingers dance on the up and down,

The black and white keys are alternating,

The beautiful piano sounds refreshing,

The moving echo is touching ...

See Zhou Dong and Lang Lang fighting piano,

We are intoxicated by the music world,

Have you ever thought about the piano question:

How does the piano speak?

How does the piano pedal work?

Why is the piano sound strong and weak?

Why is it sometimes long and short?

Let us know the piano more detailed,

Entering its "inner world" ...

PART.

01

Vertical piano and triangle piano

Watching Zhou Dong's MV's friends must find it (please see a few more times if you didn't find it). The piano used by Douqin Zhou Dong and Lang Lang is not the same in appearance. Zhou Dong's piano is rectangular with a small size and belongs to the vertical piano; Lang Lang's piano is relatively large and belongs to the triangle piano. These are the two main types of modern piano.

Vertical piano (top) and triangle piano (bottom)

The picture comes from information 1

Although the principle of sound is consistent, the difference in shape will cause the two piano internal structures and sounds to make different sounds. First, let the piano tenderly open. (Qin: Listen to me, thank you ...)

Vice piano piano body structure

The picture comes from information 2

Piano piano strings structure signal

The picture comes from information 2

The string hammer and strings of the vertical piano strings are blocked in front of the strings. In order to expose the internal structure, the latter picture removed the hammer and strings. Simply familiar with the structure of the piano, let's take a look at the process of the piano as a whole:

Fingers press the piano keys. Due to the leverage principle, the piano keys drives the structural movement inside the strings, triggering the hammer to hit the strings. The energy of the string vibration will be passed to the sound board through the strings bridge to achieve the resonance of the strings and the sound board. Due to the large area of ​​the sound plate, the sound can be passed out loudly by driving the surrounding air vibration. Simply put, the keys are driving the hammer to hit the string, and the strings drive the sound board to vibrate.

Said the relevant structure of the triangle piano strings

The picture comes from information 4

The picture above gives a photo of the triangular piano that is not installed in the piano. In contrast, the structure is the same as the vertical piano, but they are lying flat ...

Therefore, the unified structure as shown in the figure below can be abstracted. The two ends of the strings are fixed on the string shaft nails and the end fixing point. The middle part will pass three fulcrum, which are string strips, string pillow chord code bridges. Because the string hammer of the piano string will knock on the middle part of the string pillow chord bridge, the length of the strings that actually vibrates are from the part of the string pillow to the strings bridge.

Strings and fulcrum structures

Drawing reference materials 6

Among them, the role of pressing strings is to lower the strings to 12 ° ~ 15 ° with the string pillow, so that the effective vibration is limited between the string pillow and the string horse, making the vibration lasting and reducing the noise. In addition, the smaller the area between the strings and the strings, the more conducive to the vibration of tuning and piano string, and it can keep the sound stable.

Said the triangle piano audio board

The picture comes from information 5

Piano piano audio board signal

The picture comes from information 8

Compare the sound board structure of the triangle piano and vertical piano in the two pictures. Its basic structures are resonance boards and ribs, where the ribs can assist the sound to quickly spread to the entire sound board. The material of the sound board determines the sound of the piano.

PART.

02

Vibration of the string

The vibration of the piano string after the string hammer is the core of the piano sound, so the piano can be classified as a string instrument from the perspective of the sound site. Next, you will introduce the mathematical model of piano string vibration. Friends with "formula allergies" can jump to the "formula rest symbol" to continue reading.

It can be considered that the strings are a quasi -one -dimensional model (X direction) fixed between the chord chord bridge. When the string hammer knocked, it brought the string to a vertical direction (Y direction) of the strings. The micro -division equation of this model can be written:

Among them, μ is the line density of the string, and f (x, t) is a force. Assuming the force of the strings at the strings of the string of the string of the Δt time of the knocking effect, then the differential equation writing

The boundary condition is y (0, t) = y (l, t) = 0, and the initial condition is y (x, 0) = yt (x, 0) = 0. Among them, the length of the string is L, α is the distance between the distance between the closest end point of the strings and the strings.当t & ∆t时该问题的解为

The coefficient

And according to the two simplified resonance synthesis of the same frequency, it is still a simple resonance of the same frequency. It can be written:

Definition parameter

There is

The expression of the station has

< /g> < /g> .

Formula rest

It is not difficult to see that piano vibration can be regarded as a series of different levels of resident waves. The production of the resident wave is the result of the vertical (vertical direction of the piano strings) of the piano strings transmitted and interfered back and forth between the two ends. The figure below shows the diagram of the first three -order resident wave

Qinxian 1, Two Three -Tier Wave vibration

The picture originated from information 7

It is not difficult to find by observation that the length of the strings is always an integer multiple of the half -wavelength of vibration half, that is, the wavelength

< /g> < /g> Corresponding vibration frequency

"> < /g> < /g> < /g> < /g> < /g> < /g> < /g>

The FT in the upper formula is the tension in the rope, which shows that tension or relaxation strings can change the frequency of vibration of the strings. This is exactly the principle of tuning by the string nail position through loose strings.长L is the quality of the long unit strings. It can be seen that F and L and ρL are negatively related. This shows that the longer the strings or thicker piano string, the lower the frequency of the vibration of the vibration. The reason for thick. Wait, it is safe to say that it is safe to turn to the "formula rest". How can there be formulas? Intersection Intersection

In the inherent frequency of this series, the frequency of N = 1 is the lowest frequency, called the base frequency, and the other frequency is obviously an integer multiple of the base frequency, which is called pan -frequency. Different musical instruments can play the same height sound, but the tone is completely different. This is the difference between the materials and structure that causes the general frequency.

Comparison of changes in vertical piano strings

The picture comes from information 2

In fact, there is a regulatory method of pan -frequently, which is to change the strings. Experience shows that if the strings are hit at the equal points (M is an arbitrary integer) near M, the corresponding pan -frequency of M's integer times will be weakened. The seventh and ninth order of the general instrument is unpleasant, so the strings are often set between 7 equal points and 9 and other points.

PART.

03

The structure of the strings

Looking at the basic structure of the triangular piano strings, I believe your heart will be full of question marks: Is it a small question? Is it so complicated to knock a string?

The strings of the triangle piano

The picture comes from information 12

Unfortunately, each structure is not extra ... In order to facilitate understanding, we see if it is good (back) (very) (very) point (chaotic)?

Sales of Triangle Piano Stringer Work

The picture comes from the Internet

In order to better understand, we need to start from several practical problems. First of all, we should push the hammer to the strings through a series of leverages when knocking on the piano keys. It is obviously necessary for the piano key pole, linkage device, and mallet handle. Next, the sound of the piano keys should be continuously emitted when pressing, which requires that the mallets cannot be pressed on the strings after a knocking. The rolling wheels at the rolling device and the steering section cleverly realize this.

However, when we lift the keys, the sound should be stopped. The transmission device such as the vocabulary and the corresponding lower shaft is realized, because when the keys are lifted, the vocabulator will fall on the strings to prevent it from continuing to vibrate. In the end, the pianist has the needs of continuous and quickly tapping the same keys, so the mallets should not be far away from the strings, and Tomu has realized this demand.

Piano piano striker work sign of work

The picture comes from the Internet

When we compare the strings and triangle piano of the vertical piano, the difference is nothing more than setting up the entire device, so we will not introduce it separately

PART.

04

The implementation of the pedal function

Friends who have been in contact with the piano must pay attention to the three pedals under the piano. What is the function of the pedal and how is it realized? It is hard for everyone who has just learned the principle of strings.

Piano pedal

The picture comes from the Internet

Generally, the most commonly used pedal is the ones on the far right. As the name implies, when you step on the Yan Yin pedal, each sound of the subsequent performance will still sound. If you think about it, isn't this a situation where the vocabulary is failed?

Sure enough, after stepping on the Yanyin pedal, all the vocabulary will continue to lift and leave the strings. It is worth noting that the highest tones in the treble area generally do not have corresponding vocabulary, so naturally have the effect of extension.

Stepping on the Yanyin pedal

The picture comes from information 15

For the two pedals on the left, the situation of vertical piano and triangle piano is different. First introduce the vertical piano. The scooter in the middle is a weak sound pedal (or a muffled pedal), and the role is to drop a piece of cloth between the mallet and the strings. In this way, the string hammer will be tapped on the cloth to greatly weaken the volume, which can be used to prevent disturbing others during practice.

Speed ​​on the situation after stepping on the weak sound pedal

The picture comes from information 15

The far left is the weak sound pedal. In the vertical piano, the weak sound pedal is to reduce the effect of reducing the volume by reducing the distance between the string hammer and the strings.

Step on the weak soundtrack string and near the piano strings

The picture comes from information 15

In the triangular piano, the middle pedal is called the soundtrack. The function is to close the extension of the specific sound by turning off the currently pressed one or several keys. Simply put, it is to implement the function of a specific sound.

Sales of the triangle piano hammer offset

The picture comes from information 15

The pedal on the left side of the triangle piano is also a weak soundtrack, but the principle of implementation is different. In the previous picture, careful friends may have found that not a string corresponding to each string hammer. The string hammer generally corresponds to one strings in the bass area, two corresponding to the medium and low sound zone, and three corresponding in the medium and treble zone. Therefore, the 88 -key piano often has more than 220 piano string.

In the triangular piano, when the weak soundtake on the left side is stepped on, all the string hammers will turn off the side as a whole, so that the number of strings or contact strings will be reduced when knocking, thereby achieving the role of weakening the volume.

The picture comes from reference materials 1

The familiar melody echoed again in the ear again,

But the keys that appeared in my mind, the keys that emerged,

There are also agile string hams,

A dancing strings,

A group of exquisite leverage,

A piece of tall sound board ...

Finally, the piano seems to have a soul,

The wonderful music is their most beautiful voice.

Swipe up and read reference materials 1 Jay Chou's "The Great Works"

2 Do you know the internal structure and principle of the piano?

3 Che Yingying. The relationship between the internal structure of the piano and the tone [C] Humanistic academic: process and method. 2016.

4 "Piano Maintenance" 4#string column

5 adjustment of the string system (1)

Interpret the cause of piano broken strings in 65 minutes

7 The piano turned out to be like this

8 Piano Knowledge Outline Piano Basic Structure

9 Liang Zhiqiang, Xie Zhiwen. Mathematical modeling of piano strings [C] Youth Academic Conference of the Chinese Academy of Acoustics. Chinese Acoustics Society, 2005.

10 small soldiers, Song Feng, Wu Xue. Basic tutorial of physics [M]. Higher Education Press, 2008.

11 Tuning Piano Speaking, Fourier Converts Piano Play "NEVER GONNA GIVE You Up"

12HOW Does a Piano Action Work?

13Diagram-Upricht Action

14how Pianos Work -Animated Upright Piano Action

The difference between 15 vertical piano, electric piano, and triangle piano, you will choose the piano after reading it!

16 Piano has only 88 keys. Why are there more than 220 piano string?

17 What are the pedals in the middle of the triangle piano?

Edit: Cloud Kaiye

- END -